Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological b...Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.展开更多
In the extraction of potassium from salt lakes,Mg is abundant in the form of bischofite(MgCl_(2)·6H_(2)O),which is not utilized effectively,resulting in the waste of resources and environmental pressure.Anhydrous...In the extraction of potassium from salt lakes,Mg is abundant in the form of bischofite(MgCl_(2)·6H_(2)O),which is not utilized effectively,resulting in the waste of resources and environmental pressure.Anhydrous MgCl_(2) prepared by the dehydration of bischofite is a high-quality raw material for the production of Mg.However,direct calcination of MgCl_(2)·6H_(2)O in industrial dehydration processes leads to a large amount of hydrolysis.The by-products are harmful to the electrolysis process of Mg,causing problems such as sludge formation,low current efficiency,and corrosion in the electrodes.To obtain high-purity anhydrous MgCl_(2),different advanced dehydration processes have been proposed.In this review,we focus on the recent progress of the dehydration process.Firstly,we discuss the molecular structure of MgCl_(2)·6H_(2)O and explain the reason why much hydrolysis occurs in dehydration.Secondly,we introduce the specific dehydration processes,mainly divided into direct dehydration processes and indirect dehydration processes.The direct dehydration processes are classified into gas protection heating and molecular sieve dehydration process.Indirect dehydration processes are classified into thermal dehydration of ammonium carnallite(NH_(4)Cl·MgCl_(2)·6H_(2)O),thermal dehydration of potassium carnallite(KCl·MgCl_(2)·6H_(2)O),thermal decomposition of the[HAE]Cl·MgCl_(2)·6H_(2)O,organic solvent distillation,ionic liquid dehydration process and ammonia complexation process.In the meanwhile,purity of anhydrous MgCl_(2) of each dehydration process,as well as the advantages and disadvantages,is discussed.The characteristics of different processes with a simple economic budget are also given in this paper.Finally,the main challenges are evaluated with suggested directions in the future,aiming to guide the synthesis of high-purity anhydrous MgCl_(2).展开更多
Rechargeable magnesium batteries are promising alternatives to traditional lithium batteries because of the high abundance of Mg compounds in earth crust,their low toxicity,and possible favorable properties as electro...Rechargeable magnesium batteries are promising alternatives to traditional lithium batteries because of the high abundance of Mg compounds in earth crust,their low toxicity,and possible favorable properties as electrodes'material.However,Mg metal anodes face several challenges,notably the natively existence of an inactive oxide layer on their surfaces,which reduces their effectiveness.Additionally,interactions of Mg electrodes with electrolyte solutions'components can lead to the formation of insulating surface layers,that can fully block them for ions transport.This review addresses these issues by focusing on surface treatments strategies to enhance electrochemical performance of Mg anodes.It highlights chemical and physical modification techniques to prevent oxidation and inactive-layers formation,as well as their practical implications for MIBs.We also examined the impact of Mg anodes'surface engineering on their electrochemical reversibility and cycling efficiency.Finally,future research directions to improve the performance and commercial viability of magnesium anodes and advance development of high-capacity,safe,and cost-effective energy storage systems based on magnesium electrochemistry are discussed.展开更多
Magnesium-based materials,including magnesium alloys,have emerged as a promising class of biodegradable materials with potential applications in cancer therapy due to their unique properties,including biocompatibility...Magnesium-based materials,including magnesium alloys,have emerged as a promising class of biodegradable materials with potential applications in cancer therapy due to their unique properties,including biocompatibility,biodegradability,and the ability to modulate the tumor microenvironment.The main degradation products of magnesium alloys are magnesium ions(Mg^(2+)),hydrogen(H_(2)),and magnesium hydroxide(Mg(OH)_(2)).Magnesium ions can regulate tumor growth and metastasis by mediating the inflammatory response and oxidative stress,maintaining genomic stability,and affecting the tumor microenvironment.Similarly,hydrogen can inhibit tumorigenesis through antioxidant and anti-inflammatory properties.Moreover,Mg(OH)_(2) can alter the pH of the microenvironment,impacting tumorigenesis.Biodegradable magnesium alloys serve various functions in clinical applications,including,but not limited to,bonefixation,coronary stents,and drug carriers.Nonetheless,the anti-tumor mechanism associated with magnesium-based materials has not been thoroughly investigated.This review provides a comprehensive overview of the current state of magnesium-based therapies for cancer.It highlights the mechanisms of action,identifies the challenges that must be addressed,and discusses prospects for oncological applications.展开更多
The development of magnesium batteries strongly relies on the use of a Mg metal anode and its benefits of high volumetric capacity,reduction potential,low cost and improved safety,however,to date,it still lacks suffic...The development of magnesium batteries strongly relies on the use of a Mg metal anode and its benefits of high volumetric capacity,reduction potential,low cost and improved safety,however,to date,it still lacks sufficient cycling stability and reversibility.Along with the electrolyte selection,the interfacial processes can be affected by the anode itself applying electrode engineering strategies.In this study,six different Mg anode approaches–namely bare Mg metal,Mg foil with an organic and inorganic artificial solid electrolyte interphase,Mg alloy,Mg pellet and a tape-casted Mg slurry–are selected to be investigated by means of electrochemical impedance spectroscopy in Mg|Mg and Mg|S cells.While a plating/stripping overpotential asymmetry was observed and assigned to the desolvation during Mg plating,the impedance spectra of stripping and plating hardly differ for all applied anodes.In contrast,the sulfur species significantly influence the impedance response by altering the surface layer composition.By systematic process assignment of the gained spectra in Mg|Mg and Mg|S cells,specific equivalent circuit models for different anodes and cell conditions are derived.Overall,the study aims to give valuable insights into the interfacial processes of Mg anodes to support their further development toward long-lasting Mg batteries.展开更多
The aim of this study is to investigate the mechanism of magnesium isoglycyrrhizinate(MgIG)in the treatment of myocardial remodeling induced by isoproterenol(ISO)in mice.We assessed the impact of MgIG on ISO-induced m...The aim of this study is to investigate the mechanism of magnesium isoglycyrrhizinate(MgIG)in the treatment of myocardial remodeling induced by isoproterenol(ISO)in mice.We assessed the impact of MgIG on ISO-induced myocardial remodeling by activating the PI3K/AKT1 pathway.The cardiac function of mice was evaluated by echocardiography,revealing that MgIG could improve left ventricular function.Pathological staining analysis showed that MgIG could reduce the degree of myocardial injury caused by ISO.Serum data detected by ELISA demonstrated that MgIG could decrease the levels of CK-MB,MDA,and LDH while increasing the activity of GSH-Px.Western blotting analysis revealed that protein expression levels of Collagen I,BNP,Bax,cleaved caspase-3,p-PI3K,and p-AKT1 were decreased,whereas the protein expressions of Bcl-2,COX2,and SOD1 were increased upon MgIG treatment.However,the activation of the PI3K pathway reversed the cardioprotective effects of MgIG,as evidenced by the addition of PI3K activators.Taken together,our comprehensive results suggested that MgIG could improve ISO-induced myocardial remodeling,potentially through its mechanism of inhibiting the PI3K/AKT1 pathway to regulate apoptosis and oxidative stress.展开更多
In this study,a phosphate-based conversion coating(PCC)was applied as a precursor before forming silicate-fluoride(SiF)and silicate-phosphate-fluoride(SiPF)based flash-plasma electrolytic oxidation(Flash-PEO)coatings ...In this study,a phosphate-based conversion coating(PCC)was applied as a precursor before forming silicate-fluoride(SiF)and silicate-phosphate-fluoride(SiPF)based flash-plasma electrolytic oxidation(Flash-PEO)coatings on AZ31B magnesium alloy.The main novelty is the successful incorporation of calcium,zinc,manganese and phosphate species into the Flash-PEO coatings via a precursor layer rather than using the electrolyte.The precursor also led to longer lasting and more intense discharges during the PEO process,resulting in increased pore size.Corrosion studies revealed similar short-term performance for all coatings,with impedance modulus at low frequencies above 10^(7)Ωcm^(2),and slightly better performance for the SiPF-based coating.Nonetheless,the enlarged pores in the PEO coatings functionalized with the PCC precursor compromised the effectiveness of self-healing mechanisms by creating diffusion pathways for corrosive species,leading to earlier failure.These phenomena were effectively monitored by recording the open circuit potential during immersion in 0.5 wt.%NaCl solution.In summary,this study demonstrates that conversion coatings are a viable option for the functionalization of PEO coatings on magnesium alloys,as they allow for the incorporation of cationic and other species.However,it is crucial to maintain a small pore size to facilitate effective blockage through self-healing mechanisms.展开更多
Bone defects have serious economic and clinical impacts;however,despite improvements in bone defect management,the range of clinical outcomes remains limited.A variety of biomaterials have been used to treat complex b...Bone defects have serious economic and clinical impacts;however,despite improvements in bone defect management,the range of clinical outcomes remains limited.A variety of biomaterials have been used to treat complex bone defects.However,final bone repair outcomes may be adversely affected by poor osteogenic capacity and risk of infection.Consequently,therapeutic methods are required that reduce bacterial contamination and increase the use of osteogenic biomaterials.Herein,we report the preparation of poly(lactic acid-coglycolic acid)(PLGA)microspheres coloaded with magnesium(Mg^(2+))and gallium(Ga^(3+))ions(Mg-Ga@PLGA),which can fill irregular bone defects and show good biosafety.During in vitro testing,Mg-Ga@PLGA not only showed a synergistic effect on promoting osteogenic differentiation but also inhibited osteoclastic differentiation.Moreover,we found that Mg-Ga@PLGA demonstrated an antibacterial effect.During in vivo testing,Mg Ga@PLGA exhibited strong in situ osteogenic ability.In conclusion,Mg-Ga@PLGA has good potential for treating bone defects at risk of infection.展开更多
Given the alarmingly increasing rates of glaucoma worldwide and the lack of satisfactory treatments,there is a dire need to explore more feasible treatment options.Magnesium(Mg)is an essential element in maintaining t...Given the alarmingly increasing rates of glaucoma worldwide and the lack of satisfactory treatments,there is a dire need to explore more feasible treatment options.Magnesium(Mg)is an essential element in maintaining the functional and structural integrity of vital ocular tissues,but Mg and its alloys are rarely mentioned in ophthalmic applications.Our previous research found that hydroxyapatite-coated Mg(Mg@HA)shows the best biocompatibility and bioactivity,and exhibits the effect of inhibiting fibrosis after filtration surgery in the rabbit model,which is expected to be a promising material for glaucoma drainage device.In this study,we further demonstrated the anti-fibrosis effect of Mg@HA from the molecular signal level and the efficacy of implantation in the rabbit filtration surgery model.In vitro experiments showed the surface modification of Mg affects the adhesion behavior and the reorganization of cytoskeleton of Human Western blot analysis and immunofluorescence found that Mg@HA regulates the adhesion and motility of human Tenon’s capsule fibroblasts mainly by down-regulating the phosphorylation of Smad2 and Smad3 in the canonical transforming growth factor-beta(TGF-β)signaling pathway.By observing and recording the condition of filtering blebs and intraocular pressure after surgery,the effectiveness of Mg@HA applied in the rabbit filtration surgery model was further evaluated.In conclusion,the application of hydroxyapatite-coated Mg in the eye has good biocompatibility and has the potential to resist postoperative glaucoma filtration fibrosis,which may be mediated by the regulation of the TGFβ/Smad signaling pathway.展开更多
This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composi...This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composite featuring particle-rare coarse grain (CG) and particle-rich fine grain (FG) zones was successfully fabricated. Experimental results demonstrated that compared with the homogeneous structure, the dual-heterostructure composite achieved a significant increase in elongation by 116 % and a remarkable 165 % improvement in the strength-ductility product (SDP), while maintaining a high ultimate tensile strength (UTS) of 417±4 MPa. This substantial performance enhancement is primarily attributed to the additional strain hardening induced by hetero-deformation-induced (HDI) strain hardening and crack-blunting capabilities, as elucidated by microstructural characterization and crystal plasticity finite element modeling (CPFEM). Notably, the strain hardening contribution from the CG zones at the early stage of deformation (≤ 45 % of total plastic deformation amount) is minimal but increases significantly during the subsequent deformation stages. The dislocation increment rate in CG zones (219 %) is observed to be more than double that in FG zones (95 %), attributed to the large grain size and low dislocation density in CG zones, which provide more space for dislocation storage. In addition, the aggravated deformation inhomogeneity as deformation progresses leads to an increase in geometrically necessary dislocations (GNDs) generation near the heterogeneous interface, thereby enhancing HDI hardening. Fracture mechanism analysis indicated that the cracks mainly initiate in the FG region and are effectively blunted upon their propagation to the CG region, necessitating increased energy consumption and indicating higher fracture toughness for the dual-heterostructure composites. This study validates the effectiveness of the dual-heterostructure design in magnesium-based composites, providing a novel understanding of the deformation mechanism through both experimental analysis and CPFEM, paving the way for the development of high-performance, lightweight structural materials.展开更多
Rare-earth(RE) magnesium alloys have attracted lots of attention due to their excellent mechanical properties.In this work,the microstructure and mechanical properties of as-extruded 8.5Gd-4.5Y-0.8Zn-0.4Zr magnesium a...Rare-earth(RE) magnesium alloys have attracted lots of attention due to their excellent mechanical properties.In this work,the microstructure and mechanical properties of as-extruded 8.5Gd-4.5Y-0.8Zn-0.4Zr magnesium alloy under different solution treatment were examined with the optical microscope(OM),scanning electron microscope(SEM),high resolution transmission electron microscope(HRTEM),electron back-scattered diffraction(EBSD) and Instron testing machine.The results show that the ES12alloy(solution treatment for 12 h at 520℃) has the highest ultimate tensile strength(UTS) of 390 MPa with a fracture elongation of 24.5% at the co st of a minor drop in yielding strength(YS) compared to the asextruded alloy.During solution treatment,the block-shaped long period stacking ordered(LPSO) in asextruded alloy evolves into plate-shaped LPSO,which disperses at grain boundaries(GBs),and lamellar LPSO,which distributes in grains.The coexistence of plate-shaped and lamellar LPSO,which impedes the dislocations movement,and the activated dislocations are regarded as the primary reasons for mechanical properties improvement.Furthermore,the(11-21) <1-100> texture in as-extruded alloy transforms into the(11-20) <0001> texture in ES12 alloy.The average grain size increases from 3.45 μm in as-extruded alloy to 18.70 μm in ES12 alloy.The Schmid factors of {0001} <11-20>,{10-10} <11-20>,{10-11} <11-20>,and {11-22} <11-23> increase,which indicate that slip systems are more easily activated in plastic deformation.The dynamic recrystallization(DRX) grains fraction increase to 92.8% for ES12 alloy due to the particle-stimulated nucleation(PSN) mechanism triggered by block-shaped and plate-shaped LPSO.The freshly DRXed grains further weaken the texture,and reduce the dislocation density.All of these factors increase elongation of RE magnesium alloy.展开更多
Sodium(Na)and magnesium(Mg)are becoming important for making energy-storage batteries and structural materials.Herein,we develop a liquid-metal-electrode-assisted electrolysis route to producing Na and Mg with low-car...Sodium(Na)and magnesium(Mg)are becoming important for making energy-storage batteries and structural materials.Herein,we develop a liquid-metal-electrode-assisted electrolysis route to producing Na and Mg with low-carbon emissions and no chlorine gas evolution.The clean production stems from the choice of a molten NaCl-Na_(2)CO_(3) electrolyte to prevent chlorine gas evolution,an inert nickel-based anode to produce oxygen,and a liquid metal cathode to make the cathodic product sit at the bottom of the electrolytic cell.We achieve a current efficiency of>90%for the electrolytic production of liquid Na-Sn alloy.Later,Mg-Sn alloy is prepared using the obtained Na-Sn alloy to displace Mg from molten NaCl-MgCl_(2) with a displacement efficiency of>96%.Further,Na and Mg are separated from the electrolytic Na-Sn and displaced Mg-Sn alloys by vacuum distillation with a recovery rate of>92%and Sn can be reused.Using this electrolysisdisplacement-distillation(EDD)approach,we prepare Mg from seawater.The CO_(2)emission of the EDD approach is~20.6 kg CO_(2)per kg Mg,which is less than that of the Australian Magnesium(AM)electrolysis process(~25.0 kg CO_(2)per kg Mg)and less than half that of the Pidgeon process(~45.2 kg CO_(2)per kg Mg).展开更多
Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents ca...Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents can effectively alleviate both benign and malignant biliary strictures,but the plastic and metal stents that are currently used cannot degrade and nearly has no beneficial biological effects,therefore their long-term service can result into inflammation,the formation of sludges and re-obstruction of bile duct.In recent years,magnesium(Mg)metal has been received increasing attention in the field of biomedical application due to its excellent biocompatibility,adequate mechanical properties,biodegradability and other advantages,such as anti-inflammatory and anti-tumor properties.The research on biliary stents made of magnesium metals(BSMM)has also made significant progress and a series of experiments in vitro and vivo has proved their possibility.However,there are still some problems holding back BSMM’s clinical use,including rapid corrosion rate and potential harmful reaction.In this review,we would summarize the current research of BSMM,evaluate their clinical benefits,find the choke points,and discuss the solving method.展开更多
Magnesium alloy is a promising biodegradable metal material for hard tissue engineering.However,its high corrosion rate limits its application.In our previous study,we biomimetically deposited a calcium carbonate coat...Magnesium alloy is a promising biodegradable metal material for hard tissue engineering.However,its high corrosion rate limits its application.In our previous study,we biomimetically deposited a calcium carbonate coating on the surface of magnesium alloy using siloxane induction.This calcium carbonate coating demonstrated excellent in vitro biocompatibility and provided partial protection for the magnesium alloy substrate.In this study,we further enhanced the corrosion resistance of the calcium carbonate coating by treating it with stearic acid and its derivative,sodium stearate.Electrochemical corrosion tests revealed that the sodium stearate-treated calcium carbonate coating reduced the corrosion rate by two orders of magnitude.Additionally,in vitro biocompatibility assessments showed that while the biocompatibility of the sodium stearate-treated coating was slightly reduced,it remained acceptable compared to the magnesium substrate.This study builds on our previous work and offers a promising reinforcement strategy for degradable magnesium alloys in medical applications.展开更多
Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this ...Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this work,the aging-hardening response of AZ80 alloy was effectively enhanced by applying cold-rolling deformation before conducting conventional aging treatment at 200°C.Compared to the directly aged sample,the yield strength of the pre-rolling and aged sample was increased by 35 MPa.Electron microscope examination confirmed that profuse{10¯11}and{10¯11}-{10¯12}twins,consisting of high density of dislocations and stacking faults,were generated by cold rolling.Blocky or ellipsoidal Mg_(17)Al_(12)precipitates formed at the twin boundaries(TBs)during subsequent aging treatment.Crystallographic analysis indicated that the precipitates at{10¯11}TBs always held an identical Potter OR with both the matrix and twin,while the precipitates at{10¯11}-{10¯12}TBs exhibited three different ORs:Burgers OR,Potter OR and P-S OR with either the matrix or the twin.Moreover,recrystallized grains were found inside{10¯11}-{10¯12}double twins after peak-aging at 200°C,implying that precipitation and recrystallization might occur concurrently along TBs at a relatively low temperature.It was speculated that the highly stored energy inside twins and the high elastic energy between the precipitates and twins were driving factors for the occurrence of recrystallization.展开更多
A comprehensive analysis of the microstructure and defects of a thixomolded AZ91D alloy was conducted to elucidate their influences on mechanical properties.Samples were made at injection temperatures ranging from 580...A comprehensive analysis of the microstructure and defects of a thixomolded AZ91D alloy was conducted to elucidate their influences on mechanical properties.Samples were made at injection temperatures ranging from 580 to 640℃.X-ray computed tomography was used to visualize pores,and crystal plasticity finite element simulation was adopted for deformation analysis.The microstructure characterizations reveal a hierarchical cell feature composed of α-Mg and eutectic phases.With the increase of injection temperature,large cell content in the material decreases,while the strength of the alloy increases.The underlying mechanism about strength change is that coarse-grained solids experience smaller stress even in hard orientations.The sample fabricated at a moderate temperature of 620℃ exhibits the highest elongation,least quantity and lower local concentration of pores.The detachment and tearing cracks formed at lower injection temperature and defect bands formed at higher injection temperature add additional crack sources and deteriorate the ductility of the materials.展开更多
The application of machine learning in alloy design is increasingly widespread,yet traditional models still face challenges when dealing with limited datasets and complex nonlinear relationships.This work proposes an ...The application of machine learning in alloy design is increasingly widespread,yet traditional models still face challenges when dealing with limited datasets and complex nonlinear relationships.This work proposes an interpretable machine learning method based on data augmentation and reconstruction,excavating high-performance low-alloyed magnesium(Mg)alloys.The data augmentation technique expands the original dataset through Gaussian noise.The data reconstruction method reorganizes and transforms the original data to extract more representative features,significantly improving the model's generalization ability and prediction accuracy,with a coefficient of determination(R^(2))of 95.9%for the ultimate tensile strength(UTS)model and a R^(2)of 95.3%for the elongation-to-failure(EL)model.The correlation coefficient assisted screening(CCAS)method is proposed to filter low-alloyed target alloys.A new Mg-2.2Mn-0.4Zn-0.2Al-0.2Ca(MZAX2000,wt%)alloy is designed and extruded into bar at given processing parameters,achieving room-temperature strength-ductility synergy showing an excellent UTS of 395 MPa and a high EL of 17.9%.This is closely related to its hetero-structured characteristic in the as-extruded MZAX2000 alloy consisting of coarse grains(16%),fine grains(75%),and fiber regions(9%).Therefore,this work offers new insights into optimizing alloy compositions and processing parameters for attaining new high strong and ductile low-alloyed Mg alloys.展开更多
Magnesium and its alloys offer lightweight advantage and have extensive development prospects,particularly in aerospace.However,their flammability poses a significant barrier on the development of Mg alloys.The igniti...Magnesium and its alloys offer lightweight advantage and have extensive development prospects,particularly in aerospace.However,their flammability poses a significant barrier on the development of Mg alloys.The ignition resistance of these alloys often depends on the protectiveness of the oxide film formed on the surface.This paper elucidates the formation mechanism of oxide film from thermodynamics and kinetics,classifying oxide films based on their layered structure to assess their protective properties.Furthermore,it comprehensively reviews the impact of characteristics on the protective effectiveness such as compactness,continuity,thickness,and mechanical properties.The paper also introduces various characterization methods for the microstructure and properties of oxide film.The primary objective of this paper is to enhance the comprehension of oxide film concerning the ignition resistance of Mg alloys and to furnish references for future advancements and research in Mg alloys with heightened ignition resistance.展开更多
Magnesium and magnesium alloys,serving as crucial lightweight structural materials and hydrogen storage elements,find extensive applications in space technology,aviation,automotive,and magnesium-based hydrogen industr...Magnesium and magnesium alloys,serving as crucial lightweight structural materials and hydrogen storage elements,find extensive applications in space technology,aviation,automotive,and magnesium-based hydrogen industries.The global production of primary magnesium has reached approximately 1.2 million tons per year,with anticipated diversification in future applications and significant market demand.Nevertheless,approximately 80%of the world’s primary magnesium is still manufactured through the Pidgeon process,grappling with formidable issues including high energy consumption,massive carbon emission,significant resource depletion,and environmental pollution.The implementation of the relative vacuum method shows potential in breaking through technological challenges in the Pidgeon process,facilitating clean,low-carbon continuous magnesium smelting.This paper begins by introducing the principles of the relative vacuum method.Subsequently,it elucidates various innovative process routes,including relative vacuum ferrosilicon reduction,aluminum thermal reduction co-production of spinel,and aluminum thermal reduction co-production of calcium aluminate.Finally,and thermodynamic foundations of the relative vacuum,a quantitative analysis of the material,energy flows,carbon emission,and production cost for several new processes is conducted,comparing and analyzing them against the Pidgeon process.The study findings reveal that,with identical raw materials,the relative vacuum silicon thermal reduction process significantly decreases raw material consumption,energy consumption,and carbon dioxide emissions by 15.86%,30.89%,and 26.27%,respectively,compared to the Pidgeon process.The relative vacuum process,using magnesite as the raw material and aluminum as the reducing agent,has the lowest magnesium-to-feed ratio,at only 3.385.Additionally,its energy consumption and carbon dioxide emissions are the lowest,at 1.817 tce/t Mg and 7.782 t CO_(2)/t Mg,respectively.The energy consumption and carbon emissions of the relative vacuum magnesium smelting process co-producing calcium aluminate(12CaO·7Al_(2)O_(3),3CaO·Al_(2)O_(3),and CaO·Al_(2)O_(3))are highly correlated with the consumption of dolomite in the raw materials.When the reduction temperature is around 1473.15 K,the critical volume fraction of magnesium vapor for different processes varies within the range of 5%–40%.Production cost analysis shows that the relative vacuum primary magnesium smelting process has significant economic benefits.This paper offers essential data support and theoretical guidance for achieving energy efficiency,carbon reduction in magnesium smelting,and the industrial adoption of innovative processes.展开更多
A low rare-earth containing ZEK100-O magnesium alloy was welded to AA1230-clad high-strength AA2024-T3 aluminum alloy via solidstate ultrasonic spot welding(USW)to evaluate the microstructure,tensile lap shear strengt...A low rare-earth containing ZEK100-O magnesium alloy was welded to AA1230-clad high-strength AA2024-T3 aluminum alloy via solidstate ultrasonic spot welding(USW)to evaluate the microstructure,tensile lap shear strength,and fatigue properties.The tensile strength increased with increasing welding energy,peaked at a welding energy of 1000 J,and then decreased due to the formation of an increasingly thick diffusion layer mainly containing Al12Mg17intermetallic compound at higher energy levels.The peak tensile lap shear strength attained at 1000 J was attributed to the optimal inter-diffusion between the magnesium alloy and softer AA1230-clad Al layer along with the presence of‘fishhook'-like mechanical interlocks at the weld interface and the formation of an indistinguishable intermetallic layer.The dissimilar joints welded at 1000 J also exhibited a longer fatigue life than other Mg-Al dissimilar joints,suggesting the beneficial role of the softer clad layer with a better intermingling capacity during USW.While the transverse-through-thickness(TTT)failure mode prevailed at lower cyclic loading levels,interfacial failure was the predominant mode of fatigue failure at higher cyclic loads,where distinctive fatigue striations were also observed on the fracture surface of the softer clad Al layer.This was associated with the presence of opening stress and bending moment near the nugget edge despite the tension-tension lap shear cyclic loading applied.展开更多
基金support from the National Natural Science Foundation of China(grant number 52075544)Innovation Funds of Jihua Laboratory(X220971UZ230)+1 种基金Basic and Applied Basic Research Foundation of Guangdong Province(2022A1515110649)Funds from Research Platforms of Guangdong Higher Education Institutes(2022ZDJS038).
文摘Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.
基金funded by Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01F60)Tianshan Talents Plan of Xinjiang Uygur Autonomous Region(2022TSYCJC0001)+2 种基金National Natural Science Foundation of China(22368051)Science and Technology Plan Project of Karamay(20232023hjcxrc0038 and 2024hjcxrc0118)Projects of Talents Recruitment of GDUPT(2023rcyj2005)。
文摘In the extraction of potassium from salt lakes,Mg is abundant in the form of bischofite(MgCl_(2)·6H_(2)O),which is not utilized effectively,resulting in the waste of resources and environmental pressure.Anhydrous MgCl_(2) prepared by the dehydration of bischofite is a high-quality raw material for the production of Mg.However,direct calcination of MgCl_(2)·6H_(2)O in industrial dehydration processes leads to a large amount of hydrolysis.The by-products are harmful to the electrolysis process of Mg,causing problems such as sludge formation,low current efficiency,and corrosion in the electrodes.To obtain high-purity anhydrous MgCl_(2),different advanced dehydration processes have been proposed.In this review,we focus on the recent progress of the dehydration process.Firstly,we discuss the molecular structure of MgCl_(2)·6H_(2)O and explain the reason why much hydrolysis occurs in dehydration.Secondly,we introduce the specific dehydration processes,mainly divided into direct dehydration processes and indirect dehydration processes.The direct dehydration processes are classified into gas protection heating and molecular sieve dehydration process.Indirect dehydration processes are classified into thermal dehydration of ammonium carnallite(NH_(4)Cl·MgCl_(2)·6H_(2)O),thermal dehydration of potassium carnallite(KCl·MgCl_(2)·6H_(2)O),thermal decomposition of the[HAE]Cl·MgCl_(2)·6H_(2)O,organic solvent distillation,ionic liquid dehydration process and ammonia complexation process.In the meanwhile,purity of anhydrous MgCl_(2) of each dehydration process,as well as the advantages and disadvantages,is discussed.The characteristics of different processes with a simple economic budget are also given in this paper.Finally,the main challenges are evaluated with suggested directions in the future,aiming to guide the synthesis of high-purity anhydrous MgCl_(2).
基金supported by the Global Joint Research Program funded by the Pukyong National University(202411790001)the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)+2 种基金funded by the Ministry of Science and ICT(RS-2024-00446825)the Technology Innovation Program(RS-2024-00418815)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)。
文摘Rechargeable magnesium batteries are promising alternatives to traditional lithium batteries because of the high abundance of Mg compounds in earth crust,their low toxicity,and possible favorable properties as electrodes'material.However,Mg metal anodes face several challenges,notably the natively existence of an inactive oxide layer on their surfaces,which reduces their effectiveness.Additionally,interactions of Mg electrodes with electrolyte solutions'components can lead to the formation of insulating surface layers,that can fully block them for ions transport.This review addresses these issues by focusing on surface treatments strategies to enhance electrochemical performance of Mg anodes.It highlights chemical and physical modification techniques to prevent oxidation and inactive-layers formation,as well as their practical implications for MIBs.We also examined the impact of Mg anodes'surface engineering on their electrochemical reversibility and cycling efficiency.Finally,future research directions to improve the performance and commercial viability of magnesium anodes and advance development of high-capacity,safe,and cost-effective energy storage systems based on magnesium electrochemistry are discussed.
文摘Magnesium-based materials,including magnesium alloys,have emerged as a promising class of biodegradable materials with potential applications in cancer therapy due to their unique properties,including biocompatibility,biodegradability,and the ability to modulate the tumor microenvironment.The main degradation products of magnesium alloys are magnesium ions(Mg^(2+)),hydrogen(H_(2)),and magnesium hydroxide(Mg(OH)_(2)).Magnesium ions can regulate tumor growth and metastasis by mediating the inflammatory response and oxidative stress,maintaining genomic stability,and affecting the tumor microenvironment.Similarly,hydrogen can inhibit tumorigenesis through antioxidant and anti-inflammatory properties.Moreover,Mg(OH)_(2) can alter the pH of the microenvironment,impacting tumorigenesis.Biodegradable magnesium alloys serve various functions in clinical applications,including,but not limited to,bonefixation,coronary stents,and drug carriers.Nonetheless,the anti-tumor mechanism associated with magnesium-based materials has not been thoroughly investigated.This review provides a comprehensive overview of the current state of magnesium-based therapies for cancer.It highlights the mechanisms of action,identifies the challenges that must be addressed,and discusses prospects for oncological applications.
基金financially supported by the Federal Ministry for Education and Research of Germany(Bundesminis-terium für Bildung und Forschung,BMBF)and the European Commission within the projects“MagSiMal”(03XP0208)“E-MAGIC”(824066),respectively。
文摘The development of magnesium batteries strongly relies on the use of a Mg metal anode and its benefits of high volumetric capacity,reduction potential,low cost and improved safety,however,to date,it still lacks sufficient cycling stability and reversibility.Along with the electrolyte selection,the interfacial processes can be affected by the anode itself applying electrode engineering strategies.In this study,six different Mg anode approaches–namely bare Mg metal,Mg foil with an organic and inorganic artificial solid electrolyte interphase,Mg alloy,Mg pellet and a tape-casted Mg slurry–are selected to be investigated by means of electrochemical impedance spectroscopy in Mg|Mg and Mg|S cells.While a plating/stripping overpotential asymmetry was observed and assigned to the desolvation during Mg plating,the impedance spectra of stripping and plating hardly differ for all applied anodes.In contrast,the sulfur species significantly influence the impedance response by altering the surface layer composition.By systematic process assignment of the gained spectra in Mg|Mg and Mg|S cells,specific equivalent circuit models for different anodes and cell conditions are derived.Overall,the study aims to give valuable insights into the interfacial processes of Mg anodes to support their further development toward long-lasting Mg batteries.
基金Jiangxi Provincial Department of Education Science and Technology Project(Grant No.GJJ2401615)Jiangxi Provincial Department of Education Teaching Reform Project(Grant No.JXJG-24-15-15).
文摘The aim of this study is to investigate the mechanism of magnesium isoglycyrrhizinate(MgIG)in the treatment of myocardial remodeling induced by isoproterenol(ISO)in mice.We assessed the impact of MgIG on ISO-induced myocardial remodeling by activating the PI3K/AKT1 pathway.The cardiac function of mice was evaluated by echocardiography,revealing that MgIG could improve left ventricular function.Pathological staining analysis showed that MgIG could reduce the degree of myocardial injury caused by ISO.Serum data detected by ELISA demonstrated that MgIG could decrease the levels of CK-MB,MDA,and LDH while increasing the activity of GSH-Px.Western blotting analysis revealed that protein expression levels of Collagen I,BNP,Bax,cleaved caspase-3,p-PI3K,and p-AKT1 were decreased,whereas the protein expressions of Bcl-2,COX2,and SOD1 were increased upon MgIG treatment.However,the activation of the PI3K pathway reversed the cardioprotective effects of MgIG,as evidenced by the addition of PI3K activators.Taken together,our comprehensive results suggested that MgIG could improve ISO-induced myocardial remodeling,potentially through its mechanism of inhibiting the PI3K/AKT1 pathway to regulate apoptosis and oxidative stress.
基金support of the PID2021-124341OB-C22/AEI/10.13039/501100011033/FEDER,UE(MICIU)J.M.Vega also acknowledges the Grant RYC2021-034384-I funded by MICIU/AEI/10.13039/501100011033 and by“European Union Next Generation EU/PRTR”.
文摘In this study,a phosphate-based conversion coating(PCC)was applied as a precursor before forming silicate-fluoride(SiF)and silicate-phosphate-fluoride(SiPF)based flash-plasma electrolytic oxidation(Flash-PEO)coatings on AZ31B magnesium alloy.The main novelty is the successful incorporation of calcium,zinc,manganese and phosphate species into the Flash-PEO coatings via a precursor layer rather than using the electrolyte.The precursor also led to longer lasting and more intense discharges during the PEO process,resulting in increased pore size.Corrosion studies revealed similar short-term performance for all coatings,with impedance modulus at low frequencies above 10^(7)Ωcm^(2),and slightly better performance for the SiPF-based coating.Nonetheless,the enlarged pores in the PEO coatings functionalized with the PCC precursor compromised the effectiveness of self-healing mechanisms by creating diffusion pathways for corrosive species,leading to earlier failure.These phenomena were effectively monitored by recording the open circuit potential during immersion in 0.5 wt.%NaCl solution.In summary,this study demonstrates that conversion coatings are a viable option for the functionalization of PEO coatings on magnesium alloys,as they allow for the incorporation of cationic and other species.However,it is crucial to maintain a small pore size to facilitate effective blockage through self-healing mechanisms.
基金supported by grants from the National Natural Science Foundation of China(Nos.31971106,BWS21L013,and 21WS09002).
文摘Bone defects have serious economic and clinical impacts;however,despite improvements in bone defect management,the range of clinical outcomes remains limited.A variety of biomaterials have been used to treat complex bone defects.However,final bone repair outcomes may be adversely affected by poor osteogenic capacity and risk of infection.Consequently,therapeutic methods are required that reduce bacterial contamination and increase the use of osteogenic biomaterials.Herein,we report the preparation of poly(lactic acid-coglycolic acid)(PLGA)microspheres coloaded with magnesium(Mg^(2+))and gallium(Ga^(3+))ions(Mg-Ga@PLGA),which can fill irregular bone defects and show good biosafety.During in vitro testing,Mg-Ga@PLGA not only showed a synergistic effect on promoting osteogenic differentiation but also inhibited osteoclastic differentiation.Moreover,we found that Mg-Ga@PLGA demonstrated an antibacterial effect.During in vivo testing,Mg Ga@PLGA exhibited strong in situ osteogenic ability.In conclusion,Mg-Ga@PLGA has good potential for treating bone defects at risk of infection.
基金supported by the National Natural Science Foundation of China(Grant No.81670860 and 81700836)Natural Science Foundation of Chongqing(Grant No.cstc2018jcyjAX0034 and cstc2018jcyjAX0016).
文摘Given the alarmingly increasing rates of glaucoma worldwide and the lack of satisfactory treatments,there is a dire need to explore more feasible treatment options.Magnesium(Mg)is an essential element in maintaining the functional and structural integrity of vital ocular tissues,but Mg and its alloys are rarely mentioned in ophthalmic applications.Our previous research found that hydroxyapatite-coated Mg(Mg@HA)shows the best biocompatibility and bioactivity,and exhibits the effect of inhibiting fibrosis after filtration surgery in the rabbit model,which is expected to be a promising material for glaucoma drainage device.In this study,we further demonstrated the anti-fibrosis effect of Mg@HA from the molecular signal level and the efficacy of implantation in the rabbit filtration surgery model.In vitro experiments showed the surface modification of Mg affects the adhesion behavior and the reorganization of cytoskeleton of Human Western blot analysis and immunofluorescence found that Mg@HA regulates the adhesion and motility of human Tenon’s capsule fibroblasts mainly by down-regulating the phosphorylation of Smad2 and Smad3 in the canonical transforming growth factor-beta(TGF-β)signaling pathway.By observing and recording the condition of filtering blebs and intraocular pressure after surgery,the effectiveness of Mg@HA applied in the rabbit filtration surgery model was further evaluated.In conclusion,the application of hydroxyapatite-coated Mg in the eye has good biocompatibility and has the potential to resist postoperative glaucoma filtration fibrosis,which may be mediated by the regulation of the TGFβ/Smad signaling pathway.
基金support from the China Scholarship Council(No.202107000038)support from the National Natural Science Foundation of China(Nos.52004227,52061040,and 12222209)the China Postdoctoral Science Foundation(No:2021M692512).
文摘This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composite featuring particle-rare coarse grain (CG) and particle-rich fine grain (FG) zones was successfully fabricated. Experimental results demonstrated that compared with the homogeneous structure, the dual-heterostructure composite achieved a significant increase in elongation by 116 % and a remarkable 165 % improvement in the strength-ductility product (SDP), while maintaining a high ultimate tensile strength (UTS) of 417±4 MPa. This substantial performance enhancement is primarily attributed to the additional strain hardening induced by hetero-deformation-induced (HDI) strain hardening and crack-blunting capabilities, as elucidated by microstructural characterization and crystal plasticity finite element modeling (CPFEM). Notably, the strain hardening contribution from the CG zones at the early stage of deformation (≤ 45 % of total plastic deformation amount) is minimal but increases significantly during the subsequent deformation stages. The dislocation increment rate in CG zones (219 %) is observed to be more than double that in FG zones (95 %), attributed to the large grain size and low dislocation density in CG zones, which provide more space for dislocation storage. In addition, the aggravated deformation inhomogeneity as deformation progresses leads to an increase in geometrically necessary dislocations (GNDs) generation near the heterogeneous interface, thereby enhancing HDI hardening. Fracture mechanism analysis indicated that the cracks mainly initiate in the FG region and are effectively blunted upon their propagation to the CG region, necessitating increased energy consumption and indicating higher fracture toughness for the dual-heterostructure composites. This study validates the effectiveness of the dual-heterostructure design in magnesium-based composites, providing a novel understanding of the deformation mechanism through both experimental analysis and CPFEM, paving the way for the development of high-performance, lightweight structural materials.
基金supported by the Key Research and Development Program of Heilongjiang (2022ZX01A01)National Natural Science Foundation of China (51975167)Natural Science Foundation of Heilongjiang Province(LH2022E080)。
文摘Rare-earth(RE) magnesium alloys have attracted lots of attention due to their excellent mechanical properties.In this work,the microstructure and mechanical properties of as-extruded 8.5Gd-4.5Y-0.8Zn-0.4Zr magnesium alloy under different solution treatment were examined with the optical microscope(OM),scanning electron microscope(SEM),high resolution transmission electron microscope(HRTEM),electron back-scattered diffraction(EBSD) and Instron testing machine.The results show that the ES12alloy(solution treatment for 12 h at 520℃) has the highest ultimate tensile strength(UTS) of 390 MPa with a fracture elongation of 24.5% at the co st of a minor drop in yielding strength(YS) compared to the asextruded alloy.During solution treatment,the block-shaped long period stacking ordered(LPSO) in asextruded alloy evolves into plate-shaped LPSO,which disperses at grain boundaries(GBs),and lamellar LPSO,which distributes in grains.The coexistence of plate-shaped and lamellar LPSO,which impedes the dislocations movement,and the activated dislocations are regarded as the primary reasons for mechanical properties improvement.Furthermore,the(11-21) <1-100> texture in as-extruded alloy transforms into the(11-20) <0001> texture in ES12 alloy.The average grain size increases from 3.45 μm in as-extruded alloy to 18.70 μm in ES12 alloy.The Schmid factors of {0001} <11-20>,{10-10} <11-20>,{10-11} <11-20>,and {11-22} <11-23> increase,which indicate that slip systems are more easily activated in plastic deformation.The dynamic recrystallization(DRX) grains fraction increase to 92.8% for ES12 alloy due to the particle-stimulated nucleation(PSN) mechanism triggered by block-shaped and plate-shaped LPSO.The freshly DRXed grains further weaken the texture,and reduce the dislocation density.All of these factors increase elongation of RE magnesium alloy.
基金support from the National Natural Science Foundation of China(No’s.U22B2071,51874211,52031008)the Chilwee Group(CWDY-ZH-YJY-202101-001).
文摘Sodium(Na)and magnesium(Mg)are becoming important for making energy-storage batteries and structural materials.Herein,we develop a liquid-metal-electrode-assisted electrolysis route to producing Na and Mg with low-carbon emissions and no chlorine gas evolution.The clean production stems from the choice of a molten NaCl-Na_(2)CO_(3) electrolyte to prevent chlorine gas evolution,an inert nickel-based anode to produce oxygen,and a liquid metal cathode to make the cathodic product sit at the bottom of the electrolytic cell.We achieve a current efficiency of>90%for the electrolytic production of liquid Na-Sn alloy.Later,Mg-Sn alloy is prepared using the obtained Na-Sn alloy to displace Mg from molten NaCl-MgCl_(2) with a displacement efficiency of>96%.Further,Na and Mg are separated from the electrolytic Na-Sn and displaced Mg-Sn alloys by vacuum distillation with a recovery rate of>92%and Sn can be reused.Using this electrolysisdisplacement-distillation(EDD)approach,we prepare Mg from seawater.The CO_(2)emission of the EDD approach is~20.6 kg CO_(2)per kg Mg,which is less than that of the Australian Magnesium(AM)electrolysis process(~25.0 kg CO_(2)per kg Mg)and less than half that of the Pidgeon process(~45.2 kg CO_(2)per kg Mg).
基金supported by Natural Science Foundation of Hunan Province(2021JJ31081,2024JJ5619)the Science Fund of State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle(No 32215004).
文摘Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents can effectively alleviate both benign and malignant biliary strictures,but the plastic and metal stents that are currently used cannot degrade and nearly has no beneficial biological effects,therefore their long-term service can result into inflammation,the formation of sludges and re-obstruction of bile duct.In recent years,magnesium(Mg)metal has been received increasing attention in the field of biomedical application due to its excellent biocompatibility,adequate mechanical properties,biodegradability and other advantages,such as anti-inflammatory and anti-tumor properties.The research on biliary stents made of magnesium metals(BSMM)has also made significant progress and a series of experiments in vitro and vivo has proved their possibility.However,there are still some problems holding back BSMM’s clinical use,including rapid corrosion rate and potential harmful reaction.In this review,we would summarize the current research of BSMM,evaluate their clinical benefits,find the choke points,and discuss the solving method.
基金supported by the National Natural Science Foundation of China(No.52205310)the TUA research funding,UmeåUniversity/Region Västerbotten,Sweden(RV-937838)+1 种基金the Kempe foundation(JCSMK22-0122)the Natural Science Foundation of Shandong Province(No.ZR2021QE263).
文摘Magnesium alloy is a promising biodegradable metal material for hard tissue engineering.However,its high corrosion rate limits its application.In our previous study,we biomimetically deposited a calcium carbonate coating on the surface of magnesium alloy using siloxane induction.This calcium carbonate coating demonstrated excellent in vitro biocompatibility and provided partial protection for the magnesium alloy substrate.In this study,we further enhanced the corrosion resistance of the calcium carbonate coating by treating it with stearic acid and its derivative,sodium stearate.Electrochemical corrosion tests revealed that the sodium stearate-treated calcium carbonate coating reduced the corrosion rate by two orders of magnitude.Additionally,in vitro biocompatibility assessments showed that while the biocompatibility of the sodium stearate-treated coating was slightly reduced,it remained acceptable compared to the magnesium substrate.This study builds on our previous work and offers a promising reinforcement strategy for degradable magnesium alloys in medical applications.
基金financially supported by the National Natural Science Foundation of China(No.52071040 and 51871036)Natural Science Foundation of Shandong Province,China(No.ZR2022QE008)China Postdoctoral Science Foundation(No.2022M712984)。
文摘Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this work,the aging-hardening response of AZ80 alloy was effectively enhanced by applying cold-rolling deformation before conducting conventional aging treatment at 200°C.Compared to the directly aged sample,the yield strength of the pre-rolling and aged sample was increased by 35 MPa.Electron microscope examination confirmed that profuse{10¯11}and{10¯11}-{10¯12}twins,consisting of high density of dislocations and stacking faults,were generated by cold rolling.Blocky or ellipsoidal Mg_(17)Al_(12)precipitates formed at the twin boundaries(TBs)during subsequent aging treatment.Crystallographic analysis indicated that the precipitates at{10¯11}TBs always held an identical Potter OR with both the matrix and twin,while the precipitates at{10¯11}-{10¯12}TBs exhibited three different ORs:Burgers OR,Potter OR and P-S OR with either the matrix or the twin.Moreover,recrystallized grains were found inside{10¯11}-{10¯12}double twins after peak-aging at 200°C,implying that precipitation and recrystallization might occur concurrently along TBs at a relatively low temperature.It was speculated that the highly stored energy inside twins and the high elastic energy between the precipitates and twins were driving factors for the occurrence of recrystallization.
基金supported by the National Natural Science Foundation of China(Nos.51825101,52001202)the National Key Research and Development Program of China(No.2021YFA1600900)。
文摘A comprehensive analysis of the microstructure and defects of a thixomolded AZ91D alloy was conducted to elucidate their influences on mechanical properties.Samples were made at injection temperatures ranging from 580 to 640℃.X-ray computed tomography was used to visualize pores,and crystal plasticity finite element simulation was adopted for deformation analysis.The microstructure characterizations reveal a hierarchical cell feature composed of α-Mg and eutectic phases.With the increase of injection temperature,large cell content in the material decreases,while the strength of the alloy increases.The underlying mechanism about strength change is that coarse-grained solids experience smaller stress even in hard orientations.The sample fabricated at a moderate temperature of 620℃ exhibits the highest elongation,least quantity and lower local concentration of pores.The detachment and tearing cracks formed at lower injection temperature and defect bands formed at higher injection temperature add additional crack sources and deteriorate the ductility of the materials.
基金funded by the National Natural Science Foundation of China(No.52204407)the Natural Science Foundation of Jiangsu Province(No.BK20220595)+1 种基金the China Postdoctoral Science Foundation(No.2022M723689)the Industrial Collaborative Innovation Project of Shanghai(No.XTCX-KJ-2022-2-11)。
文摘The application of machine learning in alloy design is increasingly widespread,yet traditional models still face challenges when dealing with limited datasets and complex nonlinear relationships.This work proposes an interpretable machine learning method based on data augmentation and reconstruction,excavating high-performance low-alloyed magnesium(Mg)alloys.The data augmentation technique expands the original dataset through Gaussian noise.The data reconstruction method reorganizes and transforms the original data to extract more representative features,significantly improving the model's generalization ability and prediction accuracy,with a coefficient of determination(R^(2))of 95.9%for the ultimate tensile strength(UTS)model and a R^(2)of 95.3%for the elongation-to-failure(EL)model.The correlation coefficient assisted screening(CCAS)method is proposed to filter low-alloyed target alloys.A new Mg-2.2Mn-0.4Zn-0.2Al-0.2Ca(MZAX2000,wt%)alloy is designed and extruded into bar at given processing parameters,achieving room-temperature strength-ductility synergy showing an excellent UTS of 395 MPa and a high EL of 17.9%.This is closely related to its hetero-structured characteristic in the as-extruded MZAX2000 alloy consisting of coarse grains(16%),fine grains(75%),and fiber regions(9%).Therefore,this work offers new insights into optimizing alloy compositions and processing parameters for attaining new high strong and ductile low-alloyed Mg alloys.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3501002)the National Natural Science Foundation of China(Grant No.52301059,No.52271009)the Shanghai Post-doctoral Excellence Program(Grant No.2023372).
文摘Magnesium and its alloys offer lightweight advantage and have extensive development prospects,particularly in aerospace.However,their flammability poses a significant barrier on the development of Mg alloys.The ignition resistance of these alloys often depends on the protectiveness of the oxide film formed on the surface.This paper elucidates the formation mechanism of oxide film from thermodynamics and kinetics,classifying oxide films based on their layered structure to assess their protective properties.Furthermore,it comprehensively reviews the impact of characteristics on the protective effectiveness such as compactness,continuity,thickness,and mechanical properties.The paper also introduces various characterization methods for the microstructure and properties of oxide film.The primary objective of this paper is to enhance the comprehension of oxide film concerning the ignition resistance of Mg alloys and to furnish references for future advancements and research in Mg alloys with heightened ignition resistance.
基金supported by the China Postdoctoral Science Foundation(No.2023T160088)the Youth Fund of the National Natural Science Foundation of China(No.52304324).
文摘Magnesium and magnesium alloys,serving as crucial lightweight structural materials and hydrogen storage elements,find extensive applications in space technology,aviation,automotive,and magnesium-based hydrogen industries.The global production of primary magnesium has reached approximately 1.2 million tons per year,with anticipated diversification in future applications and significant market demand.Nevertheless,approximately 80%of the world’s primary magnesium is still manufactured through the Pidgeon process,grappling with formidable issues including high energy consumption,massive carbon emission,significant resource depletion,and environmental pollution.The implementation of the relative vacuum method shows potential in breaking through technological challenges in the Pidgeon process,facilitating clean,low-carbon continuous magnesium smelting.This paper begins by introducing the principles of the relative vacuum method.Subsequently,it elucidates various innovative process routes,including relative vacuum ferrosilicon reduction,aluminum thermal reduction co-production of spinel,and aluminum thermal reduction co-production of calcium aluminate.Finally,and thermodynamic foundations of the relative vacuum,a quantitative analysis of the material,energy flows,carbon emission,and production cost for several new processes is conducted,comparing and analyzing them against the Pidgeon process.The study findings reveal that,with identical raw materials,the relative vacuum silicon thermal reduction process significantly decreases raw material consumption,energy consumption,and carbon dioxide emissions by 15.86%,30.89%,and 26.27%,respectively,compared to the Pidgeon process.The relative vacuum process,using magnesite as the raw material and aluminum as the reducing agent,has the lowest magnesium-to-feed ratio,at only 3.385.Additionally,its energy consumption and carbon dioxide emissions are the lowest,at 1.817 tce/t Mg and 7.782 t CO_(2)/t Mg,respectively.The energy consumption and carbon emissions of the relative vacuum magnesium smelting process co-producing calcium aluminate(12CaO·7Al_(2)O_(3),3CaO·Al_(2)O_(3),and CaO·Al_(2)O_(3))are highly correlated with the consumption of dolomite in the raw materials.When the reduction temperature is around 1473.15 K,the critical volume fraction of magnesium vapor for different processes varies within the range of 5%–40%.Production cost analysis shows that the relative vacuum primary magnesium smelting process has significant economic benefits.This paper offers essential data support and theoretical guidance for achieving energy efficiency,carbon reduction in magnesium smelting,and the industrial adoption of innovative processes.
基金the National Natural Science Foundation of China(Grant No.51971183)supported by OU(Osaka University,Japan)program for multilateral international collaboration research in joining and welding。
文摘A low rare-earth containing ZEK100-O magnesium alloy was welded to AA1230-clad high-strength AA2024-T3 aluminum alloy via solidstate ultrasonic spot welding(USW)to evaluate the microstructure,tensile lap shear strength,and fatigue properties.The tensile strength increased with increasing welding energy,peaked at a welding energy of 1000 J,and then decreased due to the formation of an increasingly thick diffusion layer mainly containing Al12Mg17intermetallic compound at higher energy levels.The peak tensile lap shear strength attained at 1000 J was attributed to the optimal inter-diffusion between the magnesium alloy and softer AA1230-clad Al layer along with the presence of‘fishhook'-like mechanical interlocks at the weld interface and the formation of an indistinguishable intermetallic layer.The dissimilar joints welded at 1000 J also exhibited a longer fatigue life than other Mg-Al dissimilar joints,suggesting the beneficial role of the softer clad layer with a better intermingling capacity during USW.While the transverse-through-thickness(TTT)failure mode prevailed at lower cyclic loading levels,interfacial failure was the predominant mode of fatigue failure at higher cyclic loads,where distinctive fatigue striations were also observed on the fracture surface of the softer clad Al layer.This was associated with the presence of opening stress and bending moment near the nugget edge despite the tension-tension lap shear cyclic loading applied.
