To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the...To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the alloy across different planes were investigated.The anisotropy of SLM-fabricated Ti-6Al-4V alloys was analyzed,and the electron backscatter diffraction technique was used to investigate the influence of different grain types and orientations on the stress-strain distribution at various scales.Results reveal that in room-temperature compression tests at a strain rate of 10^(-3) s^(-1),both the compressive yield strength and microhardness vary along the deposition direction,indicating a certain degree of mechanical property anisotropy.The alloy exhibits a columnar microstructure;along the deposition direction,the grains appear equiaxed,and they have internal hexagonal close-packed(hcp)α/α'martensitic structure.α'phase has a preferential orientation approximately along the<0001>direction.Anisotropy arises from the high aspect ratio of columnar grains,along with the weak texture of the microstructure and low symmetry of the hcp crystal structure.展开更多
The utilization of metallized pellets in electric arc furnace represents a pivotal strategy for the iron and steel industry to attain a green transformation.However,their low melting rate limits their application,maki...The utilization of metallized pellets in electric arc furnace represents a pivotal strategy for the iron and steel industry to attain a green transformation.However,their low melting rate limits their application,making it essential to understand the melting characteristics of metallized pellet and the factors that influence their melting rate.A model of isolated metallized pellet in slag-iron bath was established and verified by published experimental data.In the molten pool formed by the melting of metallized pellet,the melting process of isolated metallized pellet can be divided into three stages:the frozen shell formation stage,the frozen shell remelting stage,and the metallized pellet parent melting stage.In addition,increasing the preheating temperature of the metallized pellet and the temperature of slag-iron bath,along with reducing size and slag content of metallized pellet,can enhance the melting efficiency.The simulation results indicate that increasing the preheating temperature of the metallized pellet to 1300 K can shorten the melting time by 74.83%;increasing the temperature of slag-iron bath to 1923 K can shorten the melting time by 21.52%;reducing the size of the metallized pellet to 15 mm can shorten the melting time by 41.21%;reducing the slag content of the metallized pellet to 30%can shorten the melting time by 22.79%.展开更多
A key component of future lunar missions is the concept of in-situ resource utilization(ISRU),which involves the use of local resources to support human missions and reduce dependence on Earth-based supplies.This pape...A key component of future lunar missions is the concept of in-situ resource utilization(ISRU),which involves the use of local resources to support human missions and reduce dependence on Earth-based supplies.This paper investigates the thermal processing capability of lunar regolith without the addition of binders,with a focus on large-scale applications for the construction of lunar habitats and infrastructure.The study used a simulant of lunar regolith found on the Schr?dinger Basin in the South Pole region.This regolith simulant consists of20 wt%basalt and 80 wt%anorthosite.Experiments were conducted using a high power CO_(2)laser to sinter and melt the regolith in a 80 mm diameter laser spot to evaluate the effectiveness of direct large area thermal processing.Results indicated that sintering begins at approximately 1180℃and reaches full melt at temperatures above 1360℃.Sintering experiments with this material revealed the formation of dense samples up to 11 mm thick,while melting experiments successfully produced larger samples by overlapping molten layers and additive manufacturing up to 50 mm thick.The energy efficiency of the sintering and melting processes was compared.The melting process was about 10 times more energy efficient than sintering in terms of material consolidation,demonstrating the promising potential of laser melting technologies of anorthosite-rich regolith for the production of structural elements.展开更多
Austenitic stainless steel(ASS)is a common material used in high-pressure hydrogen systems.Prolonged exposure to high-pressure hydrogen can cause hydrogen embrittlement(HE),raising significant safety concerns.Selectiv...Austenitic stainless steel(ASS)is a common material used in high-pressure hydrogen systems.Prolonged exposure to high-pressure hydrogen can cause hydrogen embrittlement(HE),raising significant safety concerns.Selective Laser Melting(SLM),known for its high precision,is a promising additive manufacturing technology that has been widely adopted across various industries.Studies have reported that under certain SLM manufacturing conditions and process parameters,the HE resistance of SLM ASS is significantly better than that of conventionally manufactured(CM)ASS,showing great potential for application in high-pressure hydrogen systems.Thus,studying the HE of SLM ASS is crucial for further improving the safety of high-pressure hydrogen systems.This paper provides an overview of the SLM process,reviews the mechanisms of HE and their synergistic effects,and analyzes the HE characteristics of SLM ASS.Additionally,it examines the influence of unique microstructures and SLM process variables on HE of SLM ASS and offers recommendations for future research to enhance the safety of high-pressure hydrogen systems.展开更多
To enhance the anti-corrosion performance of TC4 alloy across a wide temperature range for modern aircrafts operating in increasingly harsh environments, the (TiB+TiC) hybrid reinforced TC4 composites were prepared by...To enhance the anti-corrosion performance of TC4 alloy across a wide temperature range for modern aircrafts operating in increasingly harsh environments, the (TiB+TiC) hybrid reinforced TC4 composites were prepared by laser melting deposition (LMD) via the in-situ reaction between B_(4)C reinforcement and molten TC4 alloy. The effect of B_(4)C content (0, 0.5, 1.5, wt%) on the microstructure and room/high-temperature corrosion behaviour of the composites was investigated. Microstructural analysis revealed that the microstructure of the composites was significantly influenced by the B_(4)C content. The composite containing 0.5 wt% B_(4)C exhibited an optimal microstructure characterized by refined grains, equiaxed α-Ti transformed from lath-shaped α-Ti, well-distributed (TiB+TiC) phases with a proper amount and reduced pore/dislocation defects. This composite also demonstrated the best corrosion resistance at both room temperature (25 ℃) and high temperature (800 ℃), which was primarily attributed to its comprehensive advantages including a favorable microstructure, a uniform dispersion of thermally stable (TiB+TiC) phases and a stable passivation film.展开更多
ZGH401 alloy was prepared under varying laser power levels and scanning speeds by the orthogonal test method using selective laser melting(SLM).The effect of different energy densities on microstructure and mechanical...ZGH401 alloy was prepared under varying laser power levels and scanning speeds by the orthogonal test method using selective laser melting(SLM).The effect of different energy densities on microstructure and mechanical properties of the formed alloy was investigated.The microstructure of ZGH401 was analyzed by scanning electron microscope,electron back-scattered diffraction,and electron probe microanalysis.The results show that the defects of the as-built ZGH401 are gradually reduced,the relative density is correspondingly enhanced with increasing the energy density,and the ultimate density can reach 99.6%.An increase in laser power leads to a corresponding rise in hardness of ZGH401,while a faster scanning speed reduces the residual stress in asbuilt ZGH401 samples.In addition,better tensile properties are achieved at room temperature due to more grain boundaries perpendicular to the build direction than parallel to the build direction.The precipitated phases are identified as carbides and Laves phases via chemical composition analysis,with fewer carbides observed at the molten pool boundaries than within the molten pools.展开更多
In order to increase the sustainability of future lunar missions,techniques for in-situ resource utilization(ISRU)must be developed.In this context,the local melting of lunar dust(regolith)by laser radiation for the p...In order to increase the sustainability of future lunar missions,techniques for in-situ resource utilization(ISRU)must be developed.In this context,the local melting of lunar dust(regolith)by laser radiation for the production of parts and larger structures was investigated in detail.With different experimental setups in normal and microgravity,laser spots with diameters from 5 mm to 100 mm were realized to melt the regolith simulant EAC-1A and an 80%/20%mixture of TUBS-T and TUBS-M,which are used as a substitute for the actual lunar soil.In the experiments performed,the critical parameters are the size of the laser spot,the velocity of the laser spot on the surface of the powder bed,the gravity and the wettability of the powder bed by the melt.The stability of the melt pool as a function of these parameters was investigated and it was found that the formation of a stable melt pool is determined by gravity for large melt pool sizes in the range of 50 mm and by surface tension for small melt pool sizes in the range of a few mm.展开更多
This review examines the processes of laser heating,melting,evaporation,fragmentation,and breakdown of metal nanoparticles,as well as the dependences and values of the threshold laser parameters that initiate these pr...This review examines the processes of laser heating,melting,evaporation,fragmentation,and breakdown of metal nanoparticles,as well as the dependences and values of the threshold laser parameters that initiate these processes.Literature results are analyzed from experimental studies of these processes with gold,silver,and other nanoparticles,including laser surface melting and evaporation of nanoparticles and Coulomb fragmentation of nanoparticles by ultrashort laser pulses.A theoretical model and description of the thermal mechanisms of mentioned processes with metal(solid)nanoparticles in a liquid(solid)medium,initiated by the action of laser pulses with the threshold fluences,are presented.Comparison of the obtained results with experimental data confirms the accuracy of the model and makes it possible to use them to evaluate the parameters of laser thermal processing of nanoparticles.Applications of the processes include the laser melting,reshaping,and fragmentation of nanoparticles,the formation of nanostructures and nanonetworks,the laser processing of nanoparticles located on substrates,and their cladding on surfaces in various laser nanotechnologies.The use of laser ignition,combustion,and incandescence of nanoparticles is discussed,as is the use of nanoparticle-triggered laser breakdown for spectroscopy.These laser processes are used in photothermal nanotechnologies,nanoenergy,laser processing of nanoparticles,nonlinear optical devices,high-temperature material science,etc.In general,this review presents a modern picture of the state of laser technology and high-temperature processes with nanoparticles and their applications,being focused on the latest publications with an emphasis on recent results from 2021-2024.展开更多
Selective laser melting,a predominant additive manufacturing technology for fabricating geometrically complex components,faces signifcant challenges when processing high-performance Ni-based superalloys containing ele...Selective laser melting,a predominant additive manufacturing technology for fabricating geometrically complex components,faces signifcant challenges when processing high-performance Ni-based superalloys containing elevated Al and Ti concentrations(typically>6 wt%),particularly regarding micro-cracking susceptibility.In this study,we demonstrate the successful fabrication of a novel crack-free Ni-based superalloy with 6.4 wt%(Al+Ti)content via optimized energy density,systematically investigating its microstructure,defects,and mechanical properties.Process parameter analysis revealed that insufcient energy densities led to unmolten pores,while excessively high energy densities caused keyhole formation.With an optimal energy density of 51.1 J/mm3,the crack-free superalloy exhibited exceptional mechanical properties:room temperature tensile strength of 1130 MPa with 36%elongation and elevated-temperature strength reaching 1198 MPa at 750℃.This strength enhancement correlates with the precipitation of nanoscaleγ′phases(mean size:31.56 nm)during high temperature.Furthermore,the mechanism of crack suppression is explained from multiple aspects,including energy density,grain structure,grain boundary characteristics,and the distribution of secondary phases.The absence of low-melting-point eutectic phases and brittle phases during the printing process is also explained from the perspective of alloy composition.These fndings provide a comprehensive framework for alloy design and process optimization in additive manufacturing of defect-resistant Ni-based superalloys.展开更多
Al_(0.5)CrFeNi_(2.5)high-entropy alloy(HEA)was reinforced by the small-radius Si.Al_(0.5)CrFeNi_(2.5)Six(x=0 and 0.25)HEAs were fabricated by laser melting deposition.The evolution of microstructure,nanohardness,and w...Al_(0.5)CrFeNi_(2.5)high-entropy alloy(HEA)was reinforced by the small-radius Si.Al_(0.5)CrFeNi_(2.5)Six(x=0 and 0.25)HEAs were fabricated by laser melting deposition.The evolution of microstructure,nanohardness,and wear properties of Al_(0.5)CrFeNi_(2.5)Six(x=0 and 0.25)HEAs were systematically investigated.Al_(0.5)CrFeNi_(2.5)HEA exhibits a face-centered cubic(FCC)matrix with Ni3Al-type ordered nanoprecipitates.When Si was doped,σphase and Cr-rich nanoprecipitates existed in the B2 matrix and L12 in the FCC matrix.The nanohardness was increased from 4.67 to 5.45 GPa with doping of Si,which is associated with forming the new phases and improved nanohardness of L12/FCC phases.The coefficient of friction(COF)value was reduced from 0.75 to 0.67 by adding Si.σphase and Cr-rich nanoprecipitates in B2 matrix support a decreased wear rate from 7.87×10^(-4) to 6.82×10^(-4) mm^(3)/(N m).Furthermore,the main wear mechanism of Al_(0.5)CrFeNi_(2.5)and Al_(0.5)CrFeNi_(2.5)Si0.25 HEAs is abrasive wear.展开更多
Selective laser melting(SLM)is a cost-effective 3 D metal additive manufacturing(AM)process.However,AM 316 L stainless steel(SS)has different surface and microstructure properties as compared to conventional ones.Bori...Selective laser melting(SLM)is a cost-effective 3 D metal additive manufacturing(AM)process.However,AM 316 L stainless steel(SS)has different surface and microstructure properties as compared to conventional ones.Boriding process is one of the ways to modify and increase the surface properties.The aim of this study is to predict and understand the growth kinetic of iron boride layers on AM 316 L SS.In this study,the growth kinetic mechanism was evaluated for AM 316 L SS.Pack boriding was applied at 850,900 and 950℃,each for 2,4 and 6 h.The thickness of the boride layers ranged from(1.8±0.3)μm to(27.7±2.2)μm.A diffusion model based on error function solutions in Fick’s second law was proposed to quantitatively predict and elucidate the growth rate of FeB and Fe_(2)B phase layers.The activation energy(Q)values for boron diffusion in FeB layer,Fe_(2)B layer,and dual FeB+Fe_(2)B layer were found to be 256.56,161.61 and 209.014 kJ/mol,respectively,which were higher than the conventional 316 L SS.The findings might provide and open new directions and approaches for applications of additively manufactured steels.展开更多
Continental intraplate basalts form by partial melting of the mantle,and can provide important constraints on mantle heterogeneity.However,due to the thick overlying continental lithosphere,the origins of the geochemi...Continental intraplate basalts form by partial melting of the mantle,and can provide important constraints on mantle heterogeneity.However,due to the thick overlying continental lithosphere,the origins of the geochemical characteristics of continental intraplate basalts are controversial.In this study,we examined the geochemistry of Cenozoic basalts in southeast China.These basalts which are divided into four volcanic belts exhibit a DMM-EM2 mixing trend and spatial variations in Pb isotopes from inland(i.e.,thick lithosphere)to coastal(i.e.,thin lithosphere)regions.In contrast to the Pb isotopic variations,there are no spatial variations in Sr-Nd-Hf isotopes.Marked correlations between Pb isotopes and major elements(i.e.,Mg O and Si O_(2))suggest the continental lithospheric lid controlled their petrogenesis.Nonetheless,other factors are needed to explain the variations in Ti/Ti^(*)and Hf/Hf^(*)ratios,and Nd-Hf isotopes of the southeast China basalts.The increasing Pb isotope ratios from the inner to coastal regions are associated with decreases in CaO/Al_(2)O_(3) ratios and increases in FC3MS(FeO^(T)/CaO-3×Mg O/Si O_(2);in wt.%)values,indicating contributions from non-peridotite components in the mantle sources.The similarly depleted Nd-Hf isotopic compositions of the basalts from the three inner belts indicate these basalts have a similar origin,whereas the more enriched isotopic features of the basalts from the outer belt suggest their mantle source contains older recycled oceanic crust.Thus,source(i.e.,lithological)heterogeneity also had a significant role in controlling the geochemistry of these basalts.The DMM-EM2 mixing trend defined by the Pb isotopic compositions of continental intraplate basalts from southeast China was generated by variable degrees of melting of heterogeneous mantle that was controlled by the thickness of the continental lithospheric lid(i.e.,the melting pressure).This caused variable extents of melting of enriched components in the mantle sources of the basalts(i.e.,carbonated peridotite vs.pyroxenite).展开更多
Thermophilic proteins maintain their structure and function at high temperatures,making them widely useful in industrial applications.Due to the complexity of experimental measurements,predicting the melting temperatu...Thermophilic proteins maintain their structure and function at high temperatures,making them widely useful in industrial applications.Due to the complexity of experimental measurements,predicting the melting temperature(T_(m))of proteins has become a research hotspot.Previous methods rely on amino acid composition,physicochemical properties of proteins,and the optimal growth temperature(OGT)of hosts for T_(m)prediction.However,their performance in predicting T_(m)values for thermophilic proteins(T_(m)>60℃)are generally unsatisfactory due to data scarcity.Herein,we introduce T_(m)Pred,a T_(m)prediction model for thermophilic proteins,that combines protein language model,graph convolutional network and Graphormer module.For performance evaluation,T_(m)Pred achieves a root mean square error(RMSE)of 5.48℃,a pearson correlation coefficient(P)of 0.784,and a coefficient of determination(R~2)of 0.613,representing improvements of 19%,15%,and 32%,respectively,compared to the state-of-the-art predictive models like DeepTM.Furthermore,T_(m)Pred demonstrated strong generalization capability on independent blind test datasets.Overall,T_(m)Pred provides an effective tool for the mining and modification of thermophilic proteins by leveraging deep learning.展开更多
Selective laser melting(SLM)plays a critical role in additive manufacturing,particularly in the fabrication of complex high-precision components.This study selects the AlSi10Mg alloy for its extensive use in the aeros...Selective laser melting(SLM)plays a critical role in additive manufacturing,particularly in the fabrication of complex high-precision components.This study selects the AlSi10Mg alloy for its extensive use in the aerospace and automotive industries,which require lightweight structures with superior thermal and mechanical properties.The thermal load induces residual tensile stress,leading to a decline in the geometric accuracy of the workpiece and causing cracks that reduce the fatigue life of the alloy.The rapid movement of the laser heat source during the material formation creates a localized and inhomogeneous temperature field in the powder bed.Significant temperature gradients are generated,resulting in thermal stresses and distortions within the part,affecting the quality of the molding.Therefore,understanding the effects of processing parameters and scanning strategies on the temperature field in SLM is crucial.To address these issues,this study proposes a multiscale method for predicting the complex transient temperature field during the manufacturing process based on the heat-conduction equation.Considering the influence of temperature on the material properties,a temperature-prediction model for discontinuous scanning paths in SLM and a temperature field-calculation model for irregular scanning paths are developed.The models are validated using finite-element results and are in excellent agreement.The analytical model is then used to investigate the effects of the laser power,scanning speed,and scanning spacing on the temperature distribution.The results reveal that the peak temperature decreases exponentially with increasing scanning speed and increases linearly with increasing laser power.In addition,with increasing scanning spacing,the peak temperature of the adjacent tracks near the observation point decreases linearly.These findings are critical for optimizing the SLM-process parameters and improving the material-forming quality.展开更多
Laser shock peening(LSP)was used to enhance the high-temperature oxidation resistance of laser melting deposited Ti45Al8Nb alloy.The microstructure and high-temperature oxidation behavior of the as-deposited Ti45Al8Nb...Laser shock peening(LSP)was used to enhance the high-temperature oxidation resistance of laser melting deposited Ti45Al8Nb alloy.The microstructure and high-temperature oxidation behavior of the as-deposited Ti45Al8Nb alloy before and after LSP were investigated by scanning electron microscopy,X-ray diffraction,and electron backscatter diffraction.The results indicated that the rate of mass gain in the as-deposited sample after LSP exhibited a decrease when exposed to an oxidation temperature of 900℃,implying that LSP-treated samples exhibited superior oxidation resistance at high temperatures.A gradient structure with a fine-grain layer,a deformed-grain layer,and a coarse-grain layer was formed in the LSP-treated sample,which facilitated the diffusion of the Al atom during oxidation,leading to the formation of a dense Al_(2)O_(3)layer on the surface.The mechanism of improvement in the oxidation resistance of the as-deposited Ti45Al8Nb alloy via LSP was discussed.展开更多
The melting of seasonal sea ice in Antarctica plays a pivotal role in the region’s carbon cycle,influencing global carbon storage and the exchange of carbon between the atmosphere and the ocean.However,the impact of ...The melting of seasonal sea ice in Antarctica plays a pivotal role in the region’s carbon cycle,influencing global carbon storage and the exchange of carbon between the atmosphere and the ocean.However,the impact of variability in the timing of seasonal sea ice retreat on the flux and composition of sinking particulate matter remains to be elucidated.In this study,we deployed sediment traps in Prydz Bay during the austral summers of 2019/2020 and 2020/2021,noting that sea ice melting occurred approximately one and a half months earlier in the former summer compared to the latter.We analyzed sediment trap data,which included total mass flux(TMF),particulate organic carbon(POC),biogenic silica(BSi),particulate inorganic carbon,and lithogenic particle(Litho)fluxes,as well as the stable isotopesδ^(13)C andδ^(15)N of particulate organic matter(POM).Additionally,we incorporated remote sensing data on sea ice concentration and chlorophyll a.This dramatic delay in sea ice melting timing could result in a significant increase in TMF,BSi and POC fluxes in the summer of 2020/2021 compared to 2019/2020.Elevated BSi fluxes and more ^(13)C-depleted POC in the austral summer of 2020/2021 suggest that the delayed melting of sea ice may have stimulated the productivity of centric diatoms.Furthermore,the higher BSi/POC ratio and more negativeδ^(15)N values of POM,along with a reduced presence of krill in the traps,indicate a diminished grazing pressure from zooplankton,which collectively enhanced the sedimentation efficiency of POC during the austral summer of 2020/2021.These findings highlight the critical role of sea ice melting timing in regulating productivity,flux and composition of sinking particulate matter in the Prydz Bay ecosystem,with significant implications for carbon cycling in polar oceans.展开更多
In clinical settings,tantalum(Ta)is extensively implemented as a bone implant material.Ta is highly stable and biocompatible in vivo,being one of the metallic biomaterials having high affinity for bone tissue.However,...In clinical settings,tantalum(Ta)is extensively implemented as a bone implant material.Ta is highly stable and biocompatible in vivo,being one of the metallic biomaterials having high affinity for bone tissue.However,since Ta is a refractory metal,its application as bone implant material is limited.Most recently,additive manufacturing technology has introduced a novel approach to producing Ta implants.The present study compared the microstructure,surface and mechanical characteristics,and in vitro and in vivo biological characteristics of selective laser melted Ta(SLM Ta),selective laser melted titanium alloy Ti6Al4V with Ta coating(SLM Ti6Al4V with Ta coating),and selective laser melted Ti6Al4V(SLM Ti6Al4V).Results indicate that SLM Ta possesses superior mechanical characteristics contrasted with SLM Ti6Al4V and SLM Ti6Al4V with Ta coating.Furthermore,SLM Ta has anti-inflammatory activity,excellent osseointegration performance,and osteogenic bioactivity.We fabricated an SLM porous Ta bone plate and employed it for internal fixation of ulnar and radius fractures,which has been known to promote fracture healing.Further,the SLM porous Ta bone plate could form an integrated bone plate structure with the bone tissue at the implant site.Afterward,the porous structure of the plate minimizes its elastic modulus and eliminates stress shielding,leaving no need for further surgical removal.In conclusion,the SLM porous Ta bone plate meets the performance requirements(stimulating bone regeneration,non-stress shelter,and no need for second surgery)of an ideal bone plate and may revolutionize the field of internal fixation bone plates for fractures.展开更多
Because of an unfortunate mistake during the production of this article,the Acknowledgements have been omitted.The Acknowledgements are added as follows:Sasan YAZDANI would like to thank the Scientific and Technologic...Because of an unfortunate mistake during the production of this article,the Acknowledgements have been omitted.The Acknowledgements are added as follows:Sasan YAZDANI would like to thank the Scientific and Technological Research Council of Turkey(TÜB˙ITAK)for receiving financial support for this work through the 2221 Fellowship Program for Visiting Scientists and Scientists on Sabbatical Leave(Grant ID:E 21514107-115.02-228864).Sasan YAZDANI also expresses his gratitude to Sahand University of Technology for granting him sabbatical leave to facilitate the completion of this research.展开更多
In order to obtain high-density dual-scale ceramic particles(8.5 wt.%SiC+1.5 wt.%TiC)reinforced Al-Mg Sc-Zr composites with uniform microstructure,50 nm TiC and 7μm SiC particles were pre-dispersed into 15−53μm alum...In order to obtain high-density dual-scale ceramic particles(8.5 wt.%SiC+1.5 wt.%TiC)reinforced Al-Mg Sc-Zr composites with uniform microstructure,50 nm TiC and 7μm SiC particles were pre-dispersed into 15−53μm aluminum alloy powders by low-speed ball milling and mechanical mixing technology,respectively.Then,the effects of laser energy density,power and scanning rate on the density of the composites were investigated based on selective laser melting(SLM)technology.The effect of micron-sized SiC and nano-sized TiC particles on solidification structure,mechanical properties and fracture behaviors of the composites was revealed and analyzed in detail.Interfacial reaction and phase variations in the composites with varying reinforced particles were emphatically considered.Results showed that SiC-TiC particles could significantly improve forming quality and density of the SLMed composites,and the optimal relative density was up to 100%.In the process of laser melting,a strong chemical reaction occurs between SiC and aluminum matrix,and micron-scale acicular Al_(4)SiC_(4) bands were formed in situ.There was no interfacial reaction between TiC particles and aluminum matrix.TiC/Al semi-coherent interface had good bonding strength.Pinning effect of TiC particles in grain boundaries could prevent the equiaxial crystals from growing and transforming into columnar crystals,resulting in grain refinement.The optimal ultimate tensile strength(UTS),yield strength(YS),elongation(EL)and elastic modulus of the SiC-TiC/Al-Mg-Sc-Zr composite were~394 MPa,~262 MPa,~8.2%and~86 GPa,respectively.The fracture behavior of the composites included ductile fracture of Al matrix and brittle cleavage fracture of Al_(4)SiC_(4) phases.A large number of cross-distributed acicular Al_(4)SiC_(4) bands were the main factors leading to premature failure and fracture of SiC-TiC/Al-Mg-Sc-Zr composites.展开更多
To improve the high-temperature service properties of coppery tuyere,Co06 coating with a Ni60A interlayer was prepared on copper by plasma cladding.Ni60A interlayer acted as a bridge to promote the element diffusion,t...To improve the high-temperature service properties of coppery tuyere,Co06 coating with a Ni60A interlayer was prepared on copper by plasma cladding.Ni60A interlayer acted as a bridge to promote the element diffusion,thus achieving metallurgical bonding.Due to the strengthening effect ofγ-Co,Cr_(23)C_(6)and Cr_(7)C_(3)phases,the wear resistance of Co06–Ni60A coating was much higher than that of copper substrate.As the temperature increased,the wear resistance of coating decreased first and then increased.The coating exhibited better wear resistance at 600℃ due to the oxidation wear mechanism.Compared with copper substrate and Ni60A,the oxidation resistance of Co06 was increased by 6.0 and 1.9 times,respectively.For melting loss resistance,Co06–Ni60A coating was superior to Ni60A single-layer coating,but the molten iron can still form a micro-metallurgical bonding with the coating surface.展开更多
基金National Natural Science Foundation of China(51504138,51674118,52271177)Hunan Provincial Natural Science Foundation of China(2023JJ50181)Supported by State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology(P2024-022)。
文摘To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the alloy across different planes were investigated.The anisotropy of SLM-fabricated Ti-6Al-4V alloys was analyzed,and the electron backscatter diffraction technique was used to investigate the influence of different grain types and orientations on the stress-strain distribution at various scales.Results reveal that in room-temperature compression tests at a strain rate of 10^(-3) s^(-1),both the compressive yield strength and microhardness vary along the deposition direction,indicating a certain degree of mechanical property anisotropy.The alloy exhibits a columnar microstructure;along the deposition direction,the grains appear equiaxed,and they have internal hexagonal close-packed(hcp)α/α'martensitic structure.α'phase has a preferential orientation approximately along the<0001>direction.Anisotropy arises from the high aspect ratio of columnar grains,along with the weak texture of the microstructure and low symmetry of the hcp crystal structure.
基金financially supported by China’s National Key R&D Program(Grant No.2022YFC3901403)China Baowu Low Carbon Metallurgy Innovation Foundation(Grant No.BWLCF202211)+1 种基金Fundamental Research Funds for the Central Universities(Grant No.N2225046)Program of Introducing Talents of Discipline to Universities(Grant No.B21001).
文摘The utilization of metallized pellets in electric arc furnace represents a pivotal strategy for the iron and steel industry to attain a green transformation.However,their low melting rate limits their application,making it essential to understand the melting characteristics of metallized pellet and the factors that influence their melting rate.A model of isolated metallized pellet in slag-iron bath was established and verified by published experimental data.In the molten pool formed by the melting of metallized pellet,the melting process of isolated metallized pellet can be divided into three stages:the frozen shell formation stage,the frozen shell remelting stage,and the metallized pellet parent melting stage.In addition,increasing the preheating temperature of the metallized pellet and the temperature of slag-iron bath,along with reducing size and slag content of metallized pellet,can enhance the melting efficiency.The simulation results indicate that increasing the preheating temperature of the metallized pellet to 1300 K can shorten the melting time by 74.83%;increasing the temperature of slag-iron bath to 1923 K can shorten the melting time by 21.52%;reducing the size of the metallized pellet to 15 mm can shorten the melting time by 41.21%;reducing the slag content of the metallized pellet to 30%can shorten the melting time by 22.79%.
文摘A key component of future lunar missions is the concept of in-situ resource utilization(ISRU),which involves the use of local resources to support human missions and reduce dependence on Earth-based supplies.This paper investigates the thermal processing capability of lunar regolith without the addition of binders,with a focus on large-scale applications for the construction of lunar habitats and infrastructure.The study used a simulant of lunar regolith found on the Schr?dinger Basin in the South Pole region.This regolith simulant consists of20 wt%basalt and 80 wt%anorthosite.Experiments were conducted using a high power CO_(2)laser to sinter and melt the regolith in a 80 mm diameter laser spot to evaluate the effectiveness of direct large area thermal processing.Results indicated that sintering begins at approximately 1180℃and reaches full melt at temperatures above 1360℃.Sintering experiments with this material revealed the formation of dense samples up to 11 mm thick,while melting experiments successfully produced larger samples by overlapping molten layers and additive manufacturing up to 50 mm thick.The energy efficiency of the sintering and melting processes was compared.The melting process was about 10 times more energy efficient than sintering in terms of material consolidation,demonstrating the promising potential of laser melting technologies of anorthosite-rich regolith for the production of structural elements.
基金finncially supported by the National Natural Science Foundation of China(No.52075183)the Guangdong Basic and Applied Research Fundamental(No.2023A1515010692)the Key-Area Research and Development Program of Guangdong Province(Nos.2024B1111080002 and 2020B0404020004).
文摘Austenitic stainless steel(ASS)is a common material used in high-pressure hydrogen systems.Prolonged exposure to high-pressure hydrogen can cause hydrogen embrittlement(HE),raising significant safety concerns.Selective Laser Melting(SLM),known for its high precision,is a promising additive manufacturing technology that has been widely adopted across various industries.Studies have reported that under certain SLM manufacturing conditions and process parameters,the HE resistance of SLM ASS is significantly better than that of conventionally manufactured(CM)ASS,showing great potential for application in high-pressure hydrogen systems.Thus,studying the HE of SLM ASS is crucial for further improving the safety of high-pressure hydrogen systems.This paper provides an overview of the SLM process,reviews the mechanisms of HE and their synergistic effects,and analyzes the HE characteristics of SLM ASS.Additionally,it examines the influence of unique microstructures and SLM process variables on HE of SLM ASS and offers recommendations for future research to enhance the safety of high-pressure hydrogen systems.
基金supported by the Tianjin Municipal Natural Science Foundation(No.23JCYBJC00040)the National Nat-ural Science Foundation of China(No.52175369)the Tian-jin Research Innovation Project for Postgraduate Students(No.2022SKY134).
文摘To enhance the anti-corrosion performance of TC4 alloy across a wide temperature range for modern aircrafts operating in increasingly harsh environments, the (TiB+TiC) hybrid reinforced TC4 composites were prepared by laser melting deposition (LMD) via the in-situ reaction between B_(4)C reinforcement and molten TC4 alloy. The effect of B_(4)C content (0, 0.5, 1.5, wt%) on the microstructure and room/high-temperature corrosion behaviour of the composites was investigated. Microstructural analysis revealed that the microstructure of the composites was significantly influenced by the B_(4)C content. The composite containing 0.5 wt% B_(4)C exhibited an optimal microstructure characterized by refined grains, equiaxed α-Ti transformed from lath-shaped α-Ti, well-distributed (TiB+TiC) phases with a proper amount and reduced pore/dislocation defects. This composite also demonstrated the best corrosion resistance at both room temperature (25 ℃) and high temperature (800 ℃), which was primarily attributed to its comprehensive advantages including a favorable microstructure, a uniform dispersion of thermally stable (TiB+TiC) phases and a stable passivation film.
基金National Defense Science and Technology Project Management Center(2021-JCJQ-JJ-0092)。
文摘ZGH401 alloy was prepared under varying laser power levels and scanning speeds by the orthogonal test method using selective laser melting(SLM).The effect of different energy densities on microstructure and mechanical properties of the formed alloy was investigated.The microstructure of ZGH401 was analyzed by scanning electron microscope,electron back-scattered diffraction,and electron probe microanalysis.The results show that the defects of the as-built ZGH401 are gradually reduced,the relative density is correspondingly enhanced with increasing the energy density,and the ultimate density can reach 99.6%.An increase in laser power leads to a corresponding rise in hardness of ZGH401,while a faster scanning speed reduces the residual stress in asbuilt ZGH401 samples.In addition,better tensile properties are achieved at room temperature due to more grain boundaries perpendicular to the build direction than parallel to the build direction.The precipitated phases are identified as carbides and Laves phases via chemical composition analysis,with fewer carbides observed at the molten pool boundaries than within the molten pools.
基金supported by 40th DLR Parabolic Flight Campaign and within the project"Powder based Additive Manufacturing at reduced Gravitation"(Grant No.FKZ:50WM2068)European Space Agency,OSIP Off-Earth Manufacturing and Construction Campaign(Grant No.4000134280/21/NL/GLC/mk)。
文摘In order to increase the sustainability of future lunar missions,techniques for in-situ resource utilization(ISRU)must be developed.In this context,the local melting of lunar dust(regolith)by laser radiation for the production of parts and larger structures was investigated in detail.With different experimental setups in normal and microgravity,laser spots with diameters from 5 mm to 100 mm were realized to melt the regolith simulant EAC-1A and an 80%/20%mixture of TUBS-T and TUBS-M,which are used as a substitute for the actual lunar soil.In the experiments performed,the critical parameters are the size of the laser spot,the velocity of the laser spot on the surface of the powder bed,the gravity and the wettability of the powder bed by the melt.The stability of the melt pool as a function of these parameters was investigated and it was found that the formation of a stable melt pool is determined by gravity for large melt pool sizes in the range of 50 mm and by surface tension for small melt pool sizes in the range of a few mm.
文摘This review examines the processes of laser heating,melting,evaporation,fragmentation,and breakdown of metal nanoparticles,as well as the dependences and values of the threshold laser parameters that initiate these processes.Literature results are analyzed from experimental studies of these processes with gold,silver,and other nanoparticles,including laser surface melting and evaporation of nanoparticles and Coulomb fragmentation of nanoparticles by ultrashort laser pulses.A theoretical model and description of the thermal mechanisms of mentioned processes with metal(solid)nanoparticles in a liquid(solid)medium,initiated by the action of laser pulses with the threshold fluences,are presented.Comparison of the obtained results with experimental data confirms the accuracy of the model and makes it possible to use them to evaluate the parameters of laser thermal processing of nanoparticles.Applications of the processes include the laser melting,reshaping,and fragmentation of nanoparticles,the formation of nanostructures and nanonetworks,the laser processing of nanoparticles located on substrates,and their cladding on surfaces in various laser nanotechnologies.The use of laser ignition,combustion,and incandescence of nanoparticles is discussed,as is the use of nanoparticle-triggered laser breakdown for spectroscopy.These laser processes are used in photothermal nanotechnologies,nanoenergy,laser processing of nanoparticles,nonlinear optical devices,high-temperature material science,etc.In general,this review presents a modern picture of the state of laser technology and high-temperature processes with nanoparticles and their applications,being focused on the latest publications with an emphasis on recent results from 2021-2024.
基金supported by the National Natural Science Foundation of China(Nos.51775140 and 52232004)supported by the Shenzhen Science and Technology Plan(KJZD20230923113900001).
文摘Selective laser melting,a predominant additive manufacturing technology for fabricating geometrically complex components,faces signifcant challenges when processing high-performance Ni-based superalloys containing elevated Al and Ti concentrations(typically>6 wt%),particularly regarding micro-cracking susceptibility.In this study,we demonstrate the successful fabrication of a novel crack-free Ni-based superalloy with 6.4 wt%(Al+Ti)content via optimized energy density,systematically investigating its microstructure,defects,and mechanical properties.Process parameter analysis revealed that insufcient energy densities led to unmolten pores,while excessively high energy densities caused keyhole formation.With an optimal energy density of 51.1 J/mm3,the crack-free superalloy exhibited exceptional mechanical properties:room temperature tensile strength of 1130 MPa with 36%elongation and elevated-temperature strength reaching 1198 MPa at 750℃.This strength enhancement correlates with the precipitation of nanoscaleγ′phases(mean size:31.56 nm)during high temperature.Furthermore,the mechanism of crack suppression is explained from multiple aspects,including energy density,grain structure,grain boundary characteristics,and the distribution of secondary phases.The absence of low-melting-point eutectic phases and brittle phases during the printing process is also explained from the perspective of alloy composition.These fndings provide a comprehensive framework for alloy design and process optimization in additive manufacturing of defect-resistant Ni-based superalloys.
基金supported by the China Scholarship Council(No.202208210253)the Natural Science Foundation of Liaoning Province(2022-MS-272)the Scientific Research Funding Project of the Education Department of Liaoning Province(LJKMZ20220463).
文摘Al_(0.5)CrFeNi_(2.5)high-entropy alloy(HEA)was reinforced by the small-radius Si.Al_(0.5)CrFeNi_(2.5)Six(x=0 and 0.25)HEAs were fabricated by laser melting deposition.The evolution of microstructure,nanohardness,and wear properties of Al_(0.5)CrFeNi_(2.5)Six(x=0 and 0.25)HEAs were systematically investigated.Al_(0.5)CrFeNi_(2.5)HEA exhibits a face-centered cubic(FCC)matrix with Ni3Al-type ordered nanoprecipitates.When Si was doped,σphase and Cr-rich nanoprecipitates existed in the B2 matrix and L12 in the FCC matrix.The nanohardness was increased from 4.67 to 5.45 GPa with doping of Si,which is associated with forming the new phases and improved nanohardness of L12/FCC phases.The coefficient of friction(COF)value was reduced from 0.75 to 0.67 by adding Si.σphase and Cr-rich nanoprecipitates in B2 matrix support a decreased wear rate from 7.87×10^(-4) to 6.82×10^(-4) mm^(3)/(N m).Furthermore,the main wear mechanism of Al_(0.5)CrFeNi_(2.5)and Al_(0.5)CrFeNi_(2.5)Si0.25 HEAs is abrasive wear.
文摘Selective laser melting(SLM)is a cost-effective 3 D metal additive manufacturing(AM)process.However,AM 316 L stainless steel(SS)has different surface and microstructure properties as compared to conventional ones.Boriding process is one of the ways to modify and increase the surface properties.The aim of this study is to predict and understand the growth kinetic of iron boride layers on AM 316 L SS.In this study,the growth kinetic mechanism was evaluated for AM 316 L SS.Pack boriding was applied at 850,900 and 950℃,each for 2,4 and 6 h.The thickness of the boride layers ranged from(1.8±0.3)μm to(27.7±2.2)μm.A diffusion model based on error function solutions in Fick’s second law was proposed to quantitatively predict and elucidate the growth rate of FeB and Fe_(2)B phase layers.The activation energy(Q)values for boron diffusion in FeB layer,Fe_(2)B layer,and dual FeB+Fe_(2)B layer were found to be 256.56,161.61 and 209.014 kJ/mol,respectively,which were higher than the conventional 316 L SS.The findings might provide and open new directions and approaches for applications of additively manufactured steels.
基金supported by the National Natural Science Foundation of China(No.41906051)the National Key R&D Program of China(No.2018YFE0202402)+1 种基金sponsored by the Fundamental Research Funds for the Central Universities(Tongji University)(No.22120210525)Shanghai Pilot Program for Basic Research。
文摘Continental intraplate basalts form by partial melting of the mantle,and can provide important constraints on mantle heterogeneity.However,due to the thick overlying continental lithosphere,the origins of the geochemical characteristics of continental intraplate basalts are controversial.In this study,we examined the geochemistry of Cenozoic basalts in southeast China.These basalts which are divided into four volcanic belts exhibit a DMM-EM2 mixing trend and spatial variations in Pb isotopes from inland(i.e.,thick lithosphere)to coastal(i.e.,thin lithosphere)regions.In contrast to the Pb isotopic variations,there are no spatial variations in Sr-Nd-Hf isotopes.Marked correlations between Pb isotopes and major elements(i.e.,Mg O and Si O_(2))suggest the continental lithospheric lid controlled their petrogenesis.Nonetheless,other factors are needed to explain the variations in Ti/Ti^(*)and Hf/Hf^(*)ratios,and Nd-Hf isotopes of the southeast China basalts.The increasing Pb isotope ratios from the inner to coastal regions are associated with decreases in CaO/Al_(2)O_(3) ratios and increases in FC3MS(FeO^(T)/CaO-3×Mg O/Si O_(2);in wt.%)values,indicating contributions from non-peridotite components in the mantle sources.The similarly depleted Nd-Hf isotopic compositions of the basalts from the three inner belts indicate these basalts have a similar origin,whereas the more enriched isotopic features of the basalts from the outer belt suggest their mantle source contains older recycled oceanic crust.Thus,source(i.e.,lithological)heterogeneity also had a significant role in controlling the geochemistry of these basalts.The DMM-EM2 mixing trend defined by the Pb isotopic compositions of continental intraplate basalts from southeast China was generated by variable degrees of melting of heterogeneous mantle that was controlled by the thickness of the continental lithospheric lid(i.e.,the melting pressure).This caused variable extents of melting of enriched components in the mantle sources of the basalts(i.e.,carbonated peridotite vs.pyroxenite).
基金financially supported by the National Key R&D Program of China(Nos.2020YFA0908100 and 2023YFF1204401)Shenzhen Medical Research Fund(No.B2302037)+1 种基金the National Natural Science Foundation of China(Nos.22331003 and 21925102)Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXXM-202006)。
文摘Thermophilic proteins maintain their structure and function at high temperatures,making them widely useful in industrial applications.Due to the complexity of experimental measurements,predicting the melting temperature(T_(m))of proteins has become a research hotspot.Previous methods rely on amino acid composition,physicochemical properties of proteins,and the optimal growth temperature(OGT)of hosts for T_(m)prediction.However,their performance in predicting T_(m)values for thermophilic proteins(T_(m)>60℃)are generally unsatisfactory due to data scarcity.Herein,we introduce T_(m)Pred,a T_(m)prediction model for thermophilic proteins,that combines protein language model,graph convolutional network and Graphormer module.For performance evaluation,T_(m)Pred achieves a root mean square error(RMSE)of 5.48℃,a pearson correlation coefficient(P)of 0.784,and a coefficient of determination(R~2)of 0.613,representing improvements of 19%,15%,and 32%,respectively,compared to the state-of-the-art predictive models like DeepTM.Furthermore,T_(m)Pred demonstrated strong generalization capability on independent blind test datasets.Overall,T_(m)Pred provides an effective tool for the mining and modification of thermophilic proteins by leveraging deep learning.
基金supported by National Natural Science Foundation of the China Youth Program(Grant No.52205485)Sichuan Youth Fund Program of China(Grant No.2025ZNSFSC1275)the Young Scientific Research Team Cultivation Program of SUES(Grant No.QNTD202112)。
文摘Selective laser melting(SLM)plays a critical role in additive manufacturing,particularly in the fabrication of complex high-precision components.This study selects the AlSi10Mg alloy for its extensive use in the aerospace and automotive industries,which require lightweight structures with superior thermal and mechanical properties.The thermal load induces residual tensile stress,leading to a decline in the geometric accuracy of the workpiece and causing cracks that reduce the fatigue life of the alloy.The rapid movement of the laser heat source during the material formation creates a localized and inhomogeneous temperature field in the powder bed.Significant temperature gradients are generated,resulting in thermal stresses and distortions within the part,affecting the quality of the molding.Therefore,understanding the effects of processing parameters and scanning strategies on the temperature field in SLM is crucial.To address these issues,this study proposes a multiscale method for predicting the complex transient temperature field during the manufacturing process based on the heat-conduction equation.Considering the influence of temperature on the material properties,a temperature-prediction model for discontinuous scanning paths in SLM and a temperature field-calculation model for irregular scanning paths are developed.The models are validated using finite-element results and are in excellent agreement.The analytical model is then used to investigate the effects of the laser power,scanning speed,and scanning spacing on the temperature distribution.The results reveal that the peak temperature decreases exponentially with increasing scanning speed and increases linearly with increasing laser power.In addition,with increasing scanning spacing,the peak temperature of the adjacent tracks near the observation point decreases linearly.These findings are critical for optimizing the SLM-process parameters and improving the material-forming quality.
基金supported by the Class Ⅲ Peak Discipline of Shanghai,China-Materials Science and Engineering(High-Energy Beam Intelligent Processing and Green Manufacturing).
文摘Laser shock peening(LSP)was used to enhance the high-temperature oxidation resistance of laser melting deposited Ti45Al8Nb alloy.The microstructure and high-temperature oxidation behavior of the as-deposited Ti45Al8Nb alloy before and after LSP were investigated by scanning electron microscopy,X-ray diffraction,and electron backscatter diffraction.The results indicated that the rate of mass gain in the as-deposited sample after LSP exhibited a decrease when exposed to an oxidation temperature of 900℃,implying that LSP-treated samples exhibited superior oxidation resistance at high temperatures.A gradient structure with a fine-grain layer,a deformed-grain layer,and a coarse-grain layer was formed in the LSP-treated sample,which facilitated the diffusion of the Al atom during oxidation,leading to the formation of a dense Al_(2)O_(3)layer on the surface.The mechanism of improvement in the oxidation resistance of the as-deposited Ti45Al8Nb alloy via LSP was discussed.
基金The National Key Research and Development Program of China under contract No.2022YFE0136500the Scientific Research Fund of the Second Institute of Oceanography,Ministry of Natural Resources,under contract Nos JG2212 and JG2211+2 种基金the National Natural Science Foundation of China under contract Nos 42276255,41976228,and 42176227the National Polar Special Program“Impact and Response of Antarctic Seas to Climate Change”under contract Nos IRASCC 01-01-02 and IRASCC 02-02the China Scholarship Council under contract No.201704180017.
文摘The melting of seasonal sea ice in Antarctica plays a pivotal role in the region’s carbon cycle,influencing global carbon storage and the exchange of carbon between the atmosphere and the ocean.However,the impact of variability in the timing of seasonal sea ice retreat on the flux and composition of sinking particulate matter remains to be elucidated.In this study,we deployed sediment traps in Prydz Bay during the austral summers of 2019/2020 and 2020/2021,noting that sea ice melting occurred approximately one and a half months earlier in the former summer compared to the latter.We analyzed sediment trap data,which included total mass flux(TMF),particulate organic carbon(POC),biogenic silica(BSi),particulate inorganic carbon,and lithogenic particle(Litho)fluxes,as well as the stable isotopesδ^(13)C andδ^(15)N of particulate organic matter(POM).Additionally,we incorporated remote sensing data on sea ice concentration and chlorophyll a.This dramatic delay in sea ice melting timing could result in a significant increase in TMF,BSi and POC fluxes in the summer of 2020/2021 compared to 2019/2020.Elevated BSi fluxes and more ^(13)C-depleted POC in the austral summer of 2020/2021 suggest that the delayed melting of sea ice may have stimulated the productivity of centric diatoms.Furthermore,the higher BSi/POC ratio and more negativeδ^(15)N values of POM,along with a reduced presence of krill in the traps,indicate a diminished grazing pressure from zooplankton,which collectively enhanced the sedimentation efficiency of POC during the austral summer of 2020/2021.These findings highlight the critical role of sea ice melting timing in regulating productivity,flux and composition of sinking particulate matter in the Prydz Bay ecosystem,with significant implications for carbon cycling in polar oceans.
基金supported by the National Natural Science Foundation of China(No.82172398)Liaoning Revitalization Talents Program(No.XLYC2203102).
文摘In clinical settings,tantalum(Ta)is extensively implemented as a bone implant material.Ta is highly stable and biocompatible in vivo,being one of the metallic biomaterials having high affinity for bone tissue.However,since Ta is a refractory metal,its application as bone implant material is limited.Most recently,additive manufacturing technology has introduced a novel approach to producing Ta implants.The present study compared the microstructure,surface and mechanical characteristics,and in vitro and in vivo biological characteristics of selective laser melted Ta(SLM Ta),selective laser melted titanium alloy Ti6Al4V with Ta coating(SLM Ti6Al4V with Ta coating),and selective laser melted Ti6Al4V(SLM Ti6Al4V).Results indicate that SLM Ta possesses superior mechanical characteristics contrasted with SLM Ti6Al4V and SLM Ti6Al4V with Ta coating.Furthermore,SLM Ta has anti-inflammatory activity,excellent osseointegration performance,and osteogenic bioactivity.We fabricated an SLM porous Ta bone plate and employed it for internal fixation of ulnar and radius fractures,which has been known to promote fracture healing.Further,the SLM porous Ta bone plate could form an integrated bone plate structure with the bone tissue at the implant site.Afterward,the porous structure of the plate minimizes its elastic modulus and eliminates stress shielding,leaving no need for further surgical removal.In conclusion,the SLM porous Ta bone plate meets the performance requirements(stimulating bone regeneration,non-stress shelter,and no need for second surgery)of an ideal bone plate and may revolutionize the field of internal fixation bone plates for fractures.
文摘Because of an unfortunate mistake during the production of this article,the Acknowledgements have been omitted.The Acknowledgements are added as follows:Sasan YAZDANI would like to thank the Scientific and Technological Research Council of Turkey(TÜB˙ITAK)for receiving financial support for this work through the 2221 Fellowship Program for Visiting Scientists and Scientists on Sabbatical Leave(Grant ID:E 21514107-115.02-228864).Sasan YAZDANI also expresses his gratitude to Sahand University of Technology for granting him sabbatical leave to facilitate the completion of this research.
基金Project(2022J318)supported by the Natural Science Foundation of Ningbo,ChinaProject(2021A1515110525)supported by the Guangdong Basic and Applied Basic Research Foundation,ChinaProject(2022QN05023)supported by the Inner Mongolia Natural Science Foundation Youth Project,China。
文摘In order to obtain high-density dual-scale ceramic particles(8.5 wt.%SiC+1.5 wt.%TiC)reinforced Al-Mg Sc-Zr composites with uniform microstructure,50 nm TiC and 7μm SiC particles were pre-dispersed into 15−53μm aluminum alloy powders by low-speed ball milling and mechanical mixing technology,respectively.Then,the effects of laser energy density,power and scanning rate on the density of the composites were investigated based on selective laser melting(SLM)technology.The effect of micron-sized SiC and nano-sized TiC particles on solidification structure,mechanical properties and fracture behaviors of the composites was revealed and analyzed in detail.Interfacial reaction and phase variations in the composites with varying reinforced particles were emphatically considered.Results showed that SiC-TiC particles could significantly improve forming quality and density of the SLMed composites,and the optimal relative density was up to 100%.In the process of laser melting,a strong chemical reaction occurs between SiC and aluminum matrix,and micron-scale acicular Al_(4)SiC_(4) bands were formed in situ.There was no interfacial reaction between TiC particles and aluminum matrix.TiC/Al semi-coherent interface had good bonding strength.Pinning effect of TiC particles in grain boundaries could prevent the equiaxial crystals from growing and transforming into columnar crystals,resulting in grain refinement.The optimal ultimate tensile strength(UTS),yield strength(YS),elongation(EL)and elastic modulus of the SiC-TiC/Al-Mg-Sc-Zr composite were~394 MPa,~262 MPa,~8.2%and~86 GPa,respectively.The fracture behavior of the composites included ductile fracture of Al matrix and brittle cleavage fracture of Al_(4)SiC_(4) phases.A large number of cross-distributed acicular Al_(4)SiC_(4) bands were the main factors leading to premature failure and fracture of SiC-TiC/Al-Mg-Sc-Zr composites.
基金supported by the University Synergy Innovation Program of Anhui Province(Grant Nos.GXXT-2023-025 and GXXT-2023-026)Natural Science Foundation of Anhui Province(Grant Nos.2008085ME149,2308085QE132 and 2308065ME171)Anhui University Scientific Research Project(Grant Nos.2022AH040247,2023AH051660,2023AH051670 and 2023AH051671).
文摘To improve the high-temperature service properties of coppery tuyere,Co06 coating with a Ni60A interlayer was prepared on copper by plasma cladding.Ni60A interlayer acted as a bridge to promote the element diffusion,thus achieving metallurgical bonding.Due to the strengthening effect ofγ-Co,Cr_(23)C_(6)and Cr_(7)C_(3)phases,the wear resistance of Co06–Ni60A coating was much higher than that of copper substrate.As the temperature increased,the wear resistance of coating decreased first and then increased.The coating exhibited better wear resistance at 600℃ due to the oxidation wear mechanism.Compared with copper substrate and Ni60A,the oxidation resistance of Co06 was increased by 6.0 and 1.9 times,respectively.For melting loss resistance,Co06–Ni60A coating was superior to Ni60A single-layer coating,but the molten iron can still form a micro-metallurgical bonding with the coating surface.
