Magnesium matrix composites with both high strength and ductility have been achieved by introducing pure Ti particles.However,the properties of the surfaces of the composites need to be improved by surface technology,...Magnesium matrix composites with both high strength and ductility have been achieved by introducing pure Ti particles.However,the properties of the surfaces of the composites need to be improved by surface technology,such as micro-arc oxidation(MAO).In this study,we investigated the influence of the Ti-reinforcement phase on coating growth and evolution by subjecting both AZ91 alloy and AZ91/Ti composite to MAO treatment using silicate-based and phosphate-based electrolytes.Results revealed that the Ti-reinforcement phase influenced the MAO process,altering discharge behavior,and leading to a decreased cell voltage.The vigorous discharge of the Ti-reinforcement phase induced the formation of coating discharge channels,concurrently dissolving and oxidizing Ti-reinforcement to produce a composite ceramic coating with TiO2.The MAO coating on the AZ91/Ti composite exhibited a dark blue macromorphology and distinctive local micromorphological anomalies.In silicate electrolyte,a“volcano-like”localized morphology centered on the discharge channel emerged.In contrast,treatment in phosphate-based electrolyte resulted in a coating morphology similar to typical porous ceramic coatings,with visible radial discharge micropores at the reinforcement phase location.Compared to the AZ91 alloy,the coating on the AZ91/Ti composite exhibited lower thickness and higher porosity.MAO treatment reduced the self-corrosion current density of the AZ91/Ti surface by two orders of magnitude.The silicate coating demonstrated better corrosion resistance than the phosphate coating,attributed to its lower porosity.The formation mechanism of MAO coatings on AZ91/Ti composites in phosphate-based and silicate-based electrolytes was proposed.展开更多
Magnesium alloys have gained extensive applications across various industries,including aerospace,transportation,and civil construction,owing to their excellent combinations of high specific strength and stiffness[1]....Magnesium alloys have gained extensive applications across various industries,including aerospace,transportation,and civil construction,owing to their excellent combinations of high specific strength and stiffness[1].However,their lim-ited strength due to the lack of effective strengthening phases has hindered their broader industrial applications[2].Never-theless,it has been challenging to achieve significant strength-ening due to the restricted solubility of alloying elements in magnesium[3].Thus,more and more efforts have been made to explore the concept of secondary phase-reinforced magne-sium alloys[2,4,5],where the secondary phase acts as re-inforcing agents within the magnesium matrix,resembling a composite material.展开更多
Active sulfur dissolution and shuttle effect of lithium polysulfides(LiPSs)are the main obstacles hindering the practical application of lithium-sulfur batteries(LSBs),which is primarily induced by the direct interact...Active sulfur dissolution and shuttle effect of lithium polysulfides(LiPSs)are the main obstacles hindering the practical application of lithium-sulfur batteries(LSBs),which is primarily induced by the direct interaction between sulfur-loading cathode and liquid electrolyte.The introduction of functional interlayer within the separator and cathode is an effective strategy to stabilize the electrode/electrolyte interface reaction and improve the utilization rate of active sulfur.Herein,conductive composite nanofabrics(CCN)with multifunctional groups are employed as the interlayer of sulfur-loading cathode,in which the PMIA/PAN supporting fibers offer robust mechanical strength and high thermostable performance,and gelatin/polypyrrole functional fibers ensure high electrical conductivity and strong chemical interaction for LiPSs.As demonstrated by the experimental data and material characterizations,the presence of CCN interlayer not only blocks the shuttle behavior of LiPSs,but also strengthens the interface stability of both Li anode and sulfur-loading cathode.Interestingly,the assembled LSBs with CCN interlayer can maintain stable capacity of 686 mAh/g after 200 cycles at 0.5 A/g.This work will provide new ideas for the elaborate design of functional in terlayers/se para tors for LSBs and lithium metal batteries.展开更多
The paper study the interfacial mechanical properties and structural evolution mechanisms in 6061/AZ31B/6061 composite plates with and without Ni foil interlayers.For Ni-free interfaces,a continuous diffusion layer(3....The paper study the interfacial mechanical properties and structural evolution mechanisms in 6061/AZ31B/6061 composite plates with and without Ni foil interlayers.For Ni-free interfaces,a continuous diffusion layer(3.5-4.0μm)forms,dominated by brittle columnar Al_(12)Mg_(17) intermetallic compounds(IMCs,0.27-0.35μm thick),which act as preferential crack initiation sites.In contrast,Ni foil implantation induces interfacial restructuring during hot rolling:Constrained deformation fragments the Ni foil into grid-like segments with"olive"-shaped crosssections,embedded into Mg/Al matrices.These fragments(56% areal coverage)coexist with dispersed multiphase IMCs(Mg_(2)Ni,Al_(3)Ni,Mg_(3)AlNi,Al_(12)Mg_(17);10-20 nm grains)at fragment edges,forming a hybrid interface of"willow-leaf"Al_(12)Mg_(17) islands and nanoscale Mg_(2)Ni/Al_(3)Ni layers(15-25 nm).Hall-Petch analysis reveals the multiphase IMC interface exhibits 3.6×higher"kd^(-1/2)"strengthening contribution than single-phase Al_(12)Mg_(17) systems,attributed to grain refinement(20 nm vs.260 nm average grain size).Synergistic effects of mechanical interlocking,adhesion hierarchy(Ni-Al>Ni-Mg>Al-Mg),and nanoscale reinforcement collectively enhance peel strength by 78%without compromising bulk tensile properties.展开更多
There are few studies on the preparation of magnesium matrix composites(MMCs)by rapid solidification.This study aims to add minor amounts of Ti particles to AZ91 alloy and prepare AZ91/Ti_(P) MMC ribbon by Melt-Spinni...There are few studies on the preparation of magnesium matrix composites(MMCs)by rapid solidification.This study aims to add minor amounts of Ti particles to AZ91 alloy and prepare AZ91/Ti_(P) MMC ribbon by Melt-Spinning(MS).The effects of Ti particle content on the microstructure and mechanical properties of AZ91/Ti_(P) ribbon were studied by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),X-ray diffraction(XRD),transmission electron microscopy(TEM),three-dimensional profiling(3D-P)and calculation of supercooling rate.The results show that the grain refinement of AZ91 ribbon prepared by rapid solidification is very significant and the grain refinement is further improved with the increase of Ti particle content;at the same time,the growth of β-Mg_(17)Al_(12) is inhibited,and the interface reaction between Ti and Mg leads to the formation of interfaces around Ti particles.These nano-scale Ti_(3)Al and Al_(3)Ti interface compounds uniformly wrap the Ti particles.It is believed that the addition of Ti particles not only helps to refine the surrounding grains,but also increases the dislocations in the MMC ribbon and forms a good interface,thereby improving the mechanical properties.Compared with AZ91 alloy ribbon,the yield strength and tensile strength of MMC material containing 5 wt.%Ti particles increased by 25.0%and 22.7% respectively.The elongation only decreased by 10.9%.AZ91/5 wt.%Ti_(P) ribbon has a better balance between high strength and high elongation.The analysis shows that the strengthening effect of this mechanical property is mainly attributed to fine grain strengthening,dislocation strengthening and non-basal slip.展开更多
In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The...In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.展开更多
In the field of particle reinforced magnesium(Mg)matrix composites(MMCs),the interfacial microstructures between reinforcements and Mg matrix are a subject of interest for most researchers.In this work,the 2 wt.%Ti pa...In the field of particle reinforced magnesium(Mg)matrix composites(MMCs),the interfacial microstructures between reinforcements and Mg matrix are a subject of interest for most researchers.In this work,the 2 wt.%Ti particle reinforced Mg-6Zn alloy composites with different contents(0,0.5,1,1.5,2 wt.%)of Mn were prepared using semi-solid stirring assisted ultrasonic treatment followed by hot extrusion.With the increment of Mn element,the characteristics of mixed-grain structure became obvious and the DRX was inhibited.Meanwhile,the interfacial product gradually changed from MgZn_(2)to Mn_(2)Ti.The tensile test demonstrated that the 2Ti/Mg-6Zn-1.5Mn composite exhibited an excellent strength-ductility synergy,achieving the highest yield stress(YS),ultimate tensile stress(UTS)of 239 MPa,366 MPa,respectively,along with a notable elongation(El.)of 20.6%.The increased strength is mainly due to the grain refinement,the precipitation strengthening,the HDI strengthening and the strong interfacial bonding including the tightly Ti/Mn_(2)Ti bonding and the Mn_(2)Ti/Mg coherent orientation relationship.The ideal El.is the result of fine/coarse bimodal structure and the proper interfacial reaction,which can reduce the occurrence of cracks.展开更多
In this study,AZ91D(Mg-9Al-Zn)alloys reinforced with 2 vol%TC4(Ti-6Al-4V)particles fabricated by semi-solid stir casting were extruded at different ratios,resulting in observed grain refinement effects.The research fi...In this study,AZ91D(Mg-9Al-Zn)alloys reinforced with 2 vol%TC4(Ti-6Al-4V)particles fabricated by semi-solid stir casting were extruded at different ratios,resulting in observed grain refinement effects.The research findings demonstrate that both TC4 andβ-Mg_(17)Al_(12) phases contribute to promoting dynamic recrystallization(DRX)nucleation.With increasing extrusion ratio,theβ-phase(Mg_(17)Al_(12))gradually fractures into smaller particles,leading to progressive grain refinement.Furthermore,the transition from〈01-10〉fiber texture to non-basal texture in theα-Mg matrix after hot extrusion is attributed to improved DRX behavior and activation of non-basal slip.As the extrusion ratio increases,the tensile strength and elongation(EL)of TC4_(p)/AZ91D composite improve significantly,reaching optimum comprehensive mechanical properties at an extrusion of 40:1 with a yield strength(YS)of 257 MPa,an ultimate tensile strength(UTS)of 357 MPa,and an EL of 9.7%.This remarkable strengthening effect is primarily attributed toβ-phase reinforcement,grain refinement strengthening,and strain hardening.展开更多
Achieving a balance between strength and ductility is of utmost importance for Magnesium matrix composites(MMCs).In this study,AZ31 sheets reinforced with 0.4,0.7,and 1.0 wt.%nano-TC4(Ti-6Al-4V)particles were prepared...Achieving a balance between strength and ductility is of utmost importance for Magnesium matrix composites(MMCs).In this study,AZ31 sheets reinforced with 0.4,0.7,and 1.0 wt.%nano-TC4(Ti-6Al-4V)particles were prepared by stir casting coupled with hot extrusion process.In addition to analyzing the microstructure of the extruded composite sheets,the tensile properties were also investigated.The results showed that the incorporation of nano-TC4 particles led to a reduction in texture strength and a refinement of the grains.As a result of the formation of semicoherent orientation relations at the Ti Al/Mg and Ti3Al/Mg interfaces,strong interfacial bonding was established between the TC4 nanoparticles and the AZ31 matrix.Compared with the AZ31 sheet,the composite sheet with 0.7 wt.%nano-TC4 particles exhibited the best comprehensive tensile properties.The primary factors contributing to the improvement of mechanical properties were mismatch of coefficient of thermal expansion(CTE)between TC4 nanoparticles and AZ31 matrix,grain refinement,Orowan strengthening mechanism,and strong interfacial bonding.展开更多
Magnesium matrix composites(MMCs)combine exceptional low density,high specific strength,and stiffness,positioning them as critical materials for aerospace,automotive,and electronics industries.This review highlights r...Magnesium matrix composites(MMCs)combine exceptional low density,high specific strength,and stiffness,positioning them as critical materials for aerospace,automotive,and electronics industries.This review highlights recent progress in the fabrication of Ti-Mg composites and analyzes the mechanisms behind their enhanced mechanical properties.A key focus is the interfacial deformation incompatibility between Ti and Mg phases,which generates strain gradients and promotes the accumulation of geometrically necessary dislocations(GNDs)at the interface.This process not only improves strain hardening and ductility but also reveals the need for advanced micromechanical models to capture the plastic behavior of both phases.The review critically examines the impact of different Mg matrix types(AZ,AM,VW series)and the role of interfacial product morphology and size on bonding and overall performance.Furthermore,Ti reinforcement endows the composites with superior wear resistance and thermal conductivity,indicating broad application potential.展开更多
Laminated metal composites(LMCs) are a unique composite material and have great application prospects in automobiles, ships, aircraft,and other manufacturing industries. As lightweight materials, the Mg/Al LMCs are ex...Laminated metal composites(LMCs) are a unique composite material and have great application prospects in automobiles, ships, aircraft,and other manufacturing industries. As lightweight materials, the Mg/Al LMCs are expected to combine the advantages of both Mg and Al alloys to broaden their application prospects. Roll-bonding is the most popular process for the fabrication of Mg/Al LMCs due to high production efficiency and good product quality stability. The roll-bonding process involves the deformation of the substrates and the formation of the interfacial diffusion layer. The latter will directly determine the interface bonding strength of Mg/Al LMCs. Bonding strength is very sensitive to the thickness of the reaction layer in the diffusion layer. When the thickness of the reaction layer exceeds 5 μm, the bonding strength decreases sharply. Therefore, controlling the thickness of the reaction layer is very important for the design of rolling parameters.The latest research also showed that the addition of intermediate layer metal and the construction of three-dimensional interfaces can further improve the interface bonding strength. How to apply these methods to roll-bonding is the focus of future research. Recently, a new rolling technique, corrugated roll/plat roll rolling+flat roll/flat roll rolling has been developed to fabricate Mg/Al LMCs. It can effectively promote the deformation of the hard layer and generate a wavy interface, resulting in the enhancement of the bonding quality and rolling quality.In the current review, the effects of rolling parameters and subsequent annealing on the interface structure of Mg/Al LMCs were elaborated in detail. The application of some special rolling techniques in the preparation of Mg/Al LMCs was also summarized. The latest research results on the relationship between interface structure and mechanical properties of Mg/Al LMCs were reviewed. Finally, further research directions in this field were proposed.展开更多
Currently, many gratifying signs of progress have been made in magnesium(Mg) matrix composites(MMCs) by virtue of their high mechanical properties both at room and elevated temperatures. Although the commonly used rei...Currently, many gratifying signs of progress have been made in magnesium(Mg) matrix composites(MMCs) by virtue of their high mechanical properties both at room and elevated temperatures. Although the commonly used reinforcements in MMCs are ceramic particles,they often provide improved yield and ultimate stresses by a significant loss in ductility. Therefore, hard metallic phases were introduced as alternative candidates for the manufacturing of MMCs, especially titanium(Ti). It has a high melting point, high Young’s modulus, high plasticity, low level of mutual solubility with Mg matrix, and closer thermal expansion coefficient to that of Mg metal than that of ceramic particles. It is highly preferable to provide both high ultimate stress and ductility in Mg matrix. However, many critical challenges for the fabrication of Ti-reinforced MMCs remain, such as Ti’s homogeneity, low recovery rate, and the optimization of interfacial bonding strength between Mg and Ti, etc. Meanwhile, different fabrication methods have various effects on the microstructures, mechanical properties, and the interfacial strength of Ti-reinforced MMCs. Hence, this review placed emphasis on the microstructural characteristics and mechanical properties of Ti-reinforced MMCs fabricated by different techniques. The influencing factors that govern the strengthening mechanisms were systematically compared and discussed. Future research trends, key issues, and prospects were also proposed to develop Ti-reinforced MMCs.展开更多
The compromise between strength and plasticity has greatly limited the potential application of particles reinforced magnesium matrix composites(MMCs).In this work,the Ti particles reinforced AZ31 magnesium(Mg)matrix ...The compromise between strength and plasticity has greatly limited the potential application of particles reinforced magnesium matrix composites(MMCs).In this work,the Ti particles reinforced AZ31 magnesium(Mg)matrix composites achieved simultaneous improvement in strength,elongation and wear resistance.The Ti particles reinforced AZ31 composites were fabricated by ultrasonic-assisted stir casting with hot extrusion.The results showed that a strong interfacial bonding was obtained at Ti/Mg interface because of the formation of semicoherent orientation relationship of Ti Al/Mg,Ti Al/Al_(2)Ti and Al_(2)Ti/Mg interfaces.The as-extruded 6 wt.%Ti/AZ31 composite presented the best compressive mechanical properties and wear resistance with ultimate tensile strength,elongation and wear rate of 327 MPa,20.4%and 9.026×10^(-3)mm^(3)/m,obviously higher than those of AZ31 alloys.The enhanced mechanical properties were attributed to the grain refinement and strong interfacial bonding.The improved wear resistance was closely related to the increased hardness of composites and the formation of protective oxidation films.展开更多
The coefficient of thermal expansion(CTE)mismatch between the reinforcement and the matrix results in thermal residual stresses and defects within metal-matrix composites(MMCs)upon cooling from the processing temperat...The coefficient of thermal expansion(CTE)mismatch between the reinforcement and the matrix results in thermal residual stresses and defects within metal-matrix composites(MMCs)upon cooling from the processing temperature to ambient temperature.The residual stresses and thermally induced defects play an important role in the mechanical properties of MMCs,it is critical to understand the mechanism of defect formation and evolution.This study provides atomistic simulations to reveal the generation of thermal residual stresses,dislocation and incomplete stacking fault tetrahedron(ISFT)during cooling in the idealized Cu/SiC composites.We found that dislocations are generated explosively in a certain temperature range during cooling,which results in a non-linear relationship between dislocation density and temperature.The combined effect of the stresses induced by CTE mismatch and the thermodynamic state of the metal leads to the rapid generation of dislocations.The Shockley partial and the highly stable stair rod are the two dominant dislocation structures.The immobile stair-rod dislocations and the highly stable ISFTs formed in the initial high temperature stage inhibit further development of plastic deformation.The present results provide new insights into the defect formation mechanism and the dislocation strengthening mechanism of MMCs caused by thermal mismatch between constituents.展开更多
Curve extrusion processes,including symmetric curve extrusion(SCE)and asymmetric curve extrusion(ACE)processes,were proposed to fabricate Mg-3Al-1Zn(AZ31)alloy sheets with the aim of improving planar anisotropy.For co...Curve extrusion processes,including symmetric curve extrusion(SCE)and asymmetric curve extrusion(ACE)processes,were proposed to fabricate Mg-3Al-1Zn(AZ31)alloy sheets with the aim of improving planar anisotropy.For comparison,traditional extrusion(TE)was conducted on producing AZ31 sheets.The dynamic recrystallization and flow behavior of AZ31 Mg alloy during extrusion were examined and analyzed,and the final microstructures and mechanical properties of AZ31 sheets were investigated.In comparison with the TE sheet,finer grain size,more uniform microstructure and weaker tilted basal tex-ture were achieved in the SCE and ACE sheets.Both the SCE and ACE sheets exhibited unique textures which basal poles tilted to extrusion direction(ED)and new transverse direction(TD)-tilted texture com-ponent was developed.The reasons were mainly ascribed to the introduction of additional flow velocity difference along TD during extrusion.Furthermore,the ACE sheet exhibited the lowest basal pole inten-sity,which was attributed to the introduction of extra asymmetric shear deformation during extrusion process.As a result,the ACE sheet showed the lowest yield strength and r-value,but highest elongation and n-value.Improving the planar anisotropy of AZ31 sheet was achieved by the ACE process.展开更多
In the present study,three types of bimetal composites,Al 6082 sleeve/Al 6082 core,Mg AZ31 sleeve/Mg AZ31 core and Al 6082 sleeve/Mg AZ31 core,were fabricated by drilling and assembling.The rule of mixtures(ROM)for th...In the present study,three types of bimetal composites,Al 6082 sleeve/Al 6082 core,Mg AZ31 sleeve/Mg AZ31 core and Al 6082 sleeve/Mg AZ31 core,were fabricated by drilling and assembling.The rule of mixtures(ROM)for the flow curves and yield strengths during compressive test were addressed.Our results show that the ROM can predict well the experimental flow curves and yield strengths of bimetal composites without bonding,irrespectively of the different strain hardening behavior between the two components.展开更多
A novel melting infiltration by ultrasonic vibration was investigated and applied to fabricate Ti6Al4V(TC4)lattice structure-reinforced Mg-10Gd-2Y-1Zn-xZr(refer to VW92 hereafter,x=0,0.5 wt%)alloy matrix composites.Th...A novel melting infiltration by ultrasonic vibration was investigated and applied to fabricate Ti6Al4V(TC4)lattice structure-reinforced Mg-10Gd-2Y-1Zn-xZr(refer to VW92 hereafter,x=0,0.5 wt%)alloy matrix composites.The edge-to-edge matching model indicates that the well-matching and possible orientation relationships(ORs)between theα-Mg andα-Ti,[10-10]_(α-Mg)//[11-23]_(α-Ti) in(0002)_(α-Mg)//(10-10)_(α-Ti) possesses the smallest misfit of 0.4%(f_(r)),and thus theα-Mg grains can nucleate on the TC4 lattice structure.Interfacial reaction occurred in the TC4/VW92+0.5 wt%Zr composites,and the reaction product was confirmed to be Al_(2)Zr_(3),AlZr_(2) andα-Ti(Zr)particles formed by continuous solution of Zr-Ti.Among the interfacial products,the AlZr_(2) phase is a brittle phase with high-volume fraction,which is not conducive to the load transfer.But generally speaking,theα-Ti(Zr)and theα-Mg tend to form a coherent interface,which is beneficial for improving the interfacial bonding strength of composites.展开更多
Adding Ti particles to magnesium alloy simultaneously enhances its strength and ductility.However,how these particles influence on Mg alloy’s corrosion performance is seldom reported.The corrosion behavior of AZ31-Ti...Adding Ti particles to magnesium alloy simultaneously enhances its strength and ductility.However,how these particles influence on Mg alloy’s corrosion performance is seldom reported.The corrosion behavior of AZ31-Ti composites containing titanium nanoparticles(1.5 and 5 wt%)and micron particles(10 wt%)prepared by powder metallurgical in 3.5 wt%NaCl solution was investigated.The results indicate that Ti particles serve as the primary location for the cathodic hydrogen reduction reaction,resulting in intense galvanic corrosion between the Ti and Mg matrix.Ti nanoparticles distributed at the interface of the original AZ31 powder were in a discontinuous mesh structure,thus failing to act as a barrier against corrosion.The corrosion products with the existence of numerous cracks gradually peel off during the corrosion process and cannot protect the matrix.The average corrosion rate P_(w) of AZ31,AZ31-1.5%Ti,AZ31-5%Ti,and AZ31-10%Ti after 7 days of immersion is 27.55,105.65,283.67,and 99.35 mm/y,respectively.Therefore,AZ31-Ti composites can be considered as potential candidates for degradable fracturing tools.Otherwise,it is recommended to improve their corrosion resistance through surface treatment.展开更多
The ageing behavior of as-extruded Ti_(P)/VW94 composites was investigated.The peak hardness of the composites increases compared to the matrix alloy and the 5%Ti_(P)/VW94 composite presents the highest peak hardness ...The ageing behavior of as-extruded Ti_(P)/VW94 composites was investigated.The peak hardness of the composites increases compared to the matrix alloy and the 5%Ti_(P)/VW94 composite presents the highest peak hardness of 148.7 HV after aging for about 50 h.However,the hardness increments first decrease and then slightly increase with increasing Ti particle content due to the introduction of high-density dislocations by Ti particles.展开更多
Generally,edge crack of rolled magnesium alloy sheets initiates in the RD(rolling direction)-ND(normal direction)plane and then propagate in the RD-TD(transverse direction)plane.Hence,the Mg-2Zn-1.5Mn(ZM21)alloy sheet...Generally,edge crack of rolled magnesium alloy sheets initiates in the RD(rolling direction)-ND(normal direction)plane and then propagate in the RD-TD(transverse direction)plane.Hence,the Mg-2Zn-1.5Mn(ZM21)alloy sheets with and without crack notch were designed to carry out in-situ tensile experiments under 150℃(the same temperature of rolling),with the aim to understand their crack propagation mechanism.The scanning electron microscopy(SEM)and electron backscattered diffraction(EBSD)techniques were utilized to reveal microstructural evolution in real time at designated displacements.The results show that the prismatic slip,basal slip,and extension twining play synergistic role in coordinating strain during the tensile process in ZM21 alloy sheet at 150℃.In both tensile samples with and without crack notch,localized strain is mainly concentrated at relatively fine grain area and the grain boundaries or triple junctions of the grains with large basal Schmid factor(SF)difference,which eventually leads to severe surface roughening and subsequent crack initiation.Compared with the sample without crack notch,the pre-cracked sample exhibits severer deformation at the crack tip due to strain concentration.Strain gradient distribution is observed at the crack tip region in the pre-cracked sample.The crack propagation path of the sample with pre-crack is identified and the underlying mechanism is also discussed.展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030006).
文摘Magnesium matrix composites with both high strength and ductility have been achieved by introducing pure Ti particles.However,the properties of the surfaces of the composites need to be improved by surface technology,such as micro-arc oxidation(MAO).In this study,we investigated the influence of the Ti-reinforcement phase on coating growth and evolution by subjecting both AZ91 alloy and AZ91/Ti composite to MAO treatment using silicate-based and phosphate-based electrolytes.Results revealed that the Ti-reinforcement phase influenced the MAO process,altering discharge behavior,and leading to a decreased cell voltage.The vigorous discharge of the Ti-reinforcement phase induced the formation of coating discharge channels,concurrently dissolving and oxidizing Ti-reinforcement to produce a composite ceramic coating with TiO2.The MAO coating on the AZ91/Ti composite exhibited a dark blue macromorphology and distinctive local micromorphological anomalies.In silicate electrolyte,a“volcano-like”localized morphology centered on the discharge channel emerged.In contrast,treatment in phosphate-based electrolyte resulted in a coating morphology similar to typical porous ceramic coatings,with visible radial discharge micropores at the reinforcement phase location.Compared to the AZ91 alloy,the coating on the AZ91/Ti composite exhibited lower thickness and higher porosity.MAO treatment reduced the self-corrosion current density of the AZ91/Ti surface by two orders of magnitude.The silicate coating demonstrated better corrosion resistance than the phosphate coating,attributed to its lower porosity.The formation mechanism of MAO coatings on AZ91/Ti composites in phosphate-based and silicate-based electrolytes was proposed.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030006)the Guangdong Basic and Applied Basic Research Foundation[Grant No.2021B1515120071]+1 种基金R.Shi would like to thank the financial support from the open research fund of Songshan Lake Materials Laboratory(2021SLABFK06)start-up funding from Harbin Institute of Technology(Shenzhen).
文摘Magnesium alloys have gained extensive applications across various industries,including aerospace,transportation,and civil construction,owing to their excellent combinations of high specific strength and stiffness[1].However,their lim-ited strength due to the lack of effective strengthening phases has hindered their broader industrial applications[2].Never-theless,it has been challenging to achieve significant strength-ening due to the restricted solubility of alloying elements in magnesium[3].Thus,more and more efforts have been made to explore the concept of secondary phase-reinforced magne-sium alloys[2,4,5],where the secondary phase acts as re-inforcing agents within the magnesium matrix,resembling a composite material.
基金supported by National Natural Science Foundation of China(No.22309029)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110089)+2 种基金Dongguan Social Development Technology Foundation(No.20231800907933)Collaborative Innovation Center of Marine Science and Technology of Hainan University(No.XTCX2022HYC14)Start-up Research Foundation of Hainan University(No.KYQD(ZR)-23069)。
文摘Active sulfur dissolution and shuttle effect of lithium polysulfides(LiPSs)are the main obstacles hindering the practical application of lithium-sulfur batteries(LSBs),which is primarily induced by the direct interaction between sulfur-loading cathode and liquid electrolyte.The introduction of functional interlayer within the separator and cathode is an effective strategy to stabilize the electrode/electrolyte interface reaction and improve the utilization rate of active sulfur.Herein,conductive composite nanofabrics(CCN)with multifunctional groups are employed as the interlayer of sulfur-loading cathode,in which the PMIA/PAN supporting fibers offer robust mechanical strength and high thermostable performance,and gelatin/polypyrrole functional fibers ensure high electrical conductivity and strong chemical interaction for LiPSs.As demonstrated by the experimental data and material characterizations,the presence of CCN interlayer not only blocks the shuttle behavior of LiPSs,but also strengthens the interface stability of both Li anode and sulfur-loading cathode.Interestingly,the assembled LSBs with CCN interlayer can maintain stable capacity of 686 mAh/g after 200 cycles at 0.5 A/g.This work will provide new ideas for the elaborate design of functional in terlayers/se para tors for LSBs and lithium metal batteries.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)Key Project of Chongqing Technology Innovation and Application Development Special Project(CSTB2023TIADKPX0016,CSTB2022TIAD-KPX0027)+1 种基金National Natural Science Foundation of China(51971183)the Science and Technology Program of Xinjiang Production and Construction Corps(2024AB056).
文摘The paper study the interfacial mechanical properties and structural evolution mechanisms in 6061/AZ31B/6061 composite plates with and without Ni foil interlayers.For Ni-free interfaces,a continuous diffusion layer(3.5-4.0μm)forms,dominated by brittle columnar Al_(12)Mg_(17) intermetallic compounds(IMCs,0.27-0.35μm thick),which act as preferential crack initiation sites.In contrast,Ni foil implantation induces interfacial restructuring during hot rolling:Constrained deformation fragments the Ni foil into grid-like segments with"olive"-shaped crosssections,embedded into Mg/Al matrices.These fragments(56% areal coverage)coexist with dispersed multiphase IMCs(Mg_(2)Ni,Al_(3)Ni,Mg_(3)AlNi,Al_(12)Mg_(17);10-20 nm grains)at fragment edges,forming a hybrid interface of"willow-leaf"Al_(12)Mg_(17) islands and nanoscale Mg_(2)Ni/Al_(3)Ni layers(15-25 nm).Hall-Petch analysis reveals the multiphase IMC interface exhibits 3.6×higher"kd^(-1/2)"strengthening contribution than single-phase Al_(12)Mg_(17) systems,attributed to grain refinement(20 nm vs.260 nm average grain size).Synergistic effects of mechanical interlocking,adhesion hierarchy(Ni-Al>Ni-Mg>Al-Mg),and nanoscale reinforcement collectively enhance peel strength by 78%without compromising bulk tensile properties.
基金supported by the National Key Research and Development Program of China(2022YFB3708400)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+1 种基金the Guangdong Academy of Science Fund(2020GDASYL-20200101001)Evaluation Project of Guangdong Provincial Key Laboratory(2023B1212060043).
文摘There are few studies on the preparation of magnesium matrix composites(MMCs)by rapid solidification.This study aims to add minor amounts of Ti particles to AZ91 alloy and prepare AZ91/Ti_(P) MMC ribbon by Melt-Spinning(MS).The effects of Ti particle content on the microstructure and mechanical properties of AZ91/Ti_(P) ribbon were studied by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),X-ray diffraction(XRD),transmission electron microscopy(TEM),three-dimensional profiling(3D-P)and calculation of supercooling rate.The results show that the grain refinement of AZ91 ribbon prepared by rapid solidification is very significant and the grain refinement is further improved with the increase of Ti particle content;at the same time,the growth of β-Mg_(17)Al_(12) is inhibited,and the interface reaction between Ti and Mg leads to the formation of interfaces around Ti particles.These nano-scale Ti_(3)Al and Al_(3)Ti interface compounds uniformly wrap the Ti particles.It is believed that the addition of Ti particles not only helps to refine the surrounding grains,but also increases the dislocations in the MMC ribbon and forms a good interface,thereby improving the mechanical properties.Compared with AZ91 alloy ribbon,the yield strength and tensile strength of MMC material containing 5 wt.%Ti particles increased by 25.0%and 22.7% respectively.The elongation only decreased by 10.9%.AZ91/5 wt.%Ti_(P) ribbon has a better balance between high strength and high elongation.The analysis shows that the strengthening effect of this mechanical property is mainly attributed to fine grain strengthening,dislocation strengthening and non-basal slip.
基金supported by the National Key Research and Development Program of China(2022YFB3708400)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+4 种基金the Youth Talent Support Programme of Guangdong Provincial Association for Science and Technology(SKXRC202301)the Guangdong Academy of Science Fund(2020GDASYL-20200101001,2023GDASQNRC-0210,2023GDASQNRC-0321)the Guangdong Science and Technology plan project(2023A0505030002)the GINM’Special Project of Science and Technology Development(2023GINMZX-202301020108)Evaluation Project of Guangdong Provincial Key Laboratory(2023B1212060043).
文摘In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.
基金the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)National Natural Science Foundation of China(52225101 and 52101123)+2 种基金Fundamental Research Funds for the Central Universities(2023CDJYXTD-002)Support Program for Overseas Educated Students Returning to China for Entrepreneurship and Innovation(cx2023020)Chongqing Natural Science Foundation of China(CSTB2023NSCQ-MSX0571).
文摘In the field of particle reinforced magnesium(Mg)matrix composites(MMCs),the interfacial microstructures between reinforcements and Mg matrix are a subject of interest for most researchers.In this work,the 2 wt.%Ti particle reinforced Mg-6Zn alloy composites with different contents(0,0.5,1,1.5,2 wt.%)of Mn were prepared using semi-solid stirring assisted ultrasonic treatment followed by hot extrusion.With the increment of Mn element,the characteristics of mixed-grain structure became obvious and the DRX was inhibited.Meanwhile,the interfacial product gradually changed from MgZn_(2)to Mn_(2)Ti.The tensile test demonstrated that the 2Ti/Mg-6Zn-1.5Mn composite exhibited an excellent strength-ductility synergy,achieving the highest yield stress(YS),ultimate tensile stress(UTS)of 239 MPa,366 MPa,respectively,along with a notable elongation(El.)of 20.6%.The increased strength is mainly due to the grain refinement,the precipitation strengthening,the HDI strengthening and the strong interfacial bonding including the tightly Ti/Mn_(2)Ti bonding and the Mn_(2)Ti/Mg coherent orientation relationship.The ideal El.is the result of fine/coarse bimodal structure and the proper interfacial reaction,which can reduce the occurrence of cracks.
基金the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)the Guangdong Provincial Academy of Sciences Fund(2020GDASYL-20200101001)the Natural Science Foundation of Hubei Province,China(2023AFB1033).
文摘In this study,AZ91D(Mg-9Al-Zn)alloys reinforced with 2 vol%TC4(Ti-6Al-4V)particles fabricated by semi-solid stir casting were extruded at different ratios,resulting in observed grain refinement effects.The research findings demonstrate that both TC4 andβ-Mg_(17)Al_(12) phases contribute to promoting dynamic recrystallization(DRX)nucleation.With increasing extrusion ratio,theβ-phase(Mg_(17)Al_(12))gradually fractures into smaller particles,leading to progressive grain refinement.Furthermore,the transition from〈01-10〉fiber texture to non-basal texture in theα-Mg matrix after hot extrusion is attributed to improved DRX behavior and activation of non-basal slip.As the extrusion ratio increases,the tensile strength and elongation(EL)of TC4_(p)/AZ91D composite improve significantly,reaching optimum comprehensive mechanical properties at an extrusion of 40:1 with a yield strength(YS)of 257 MPa,an ultimate tensile strength(UTS)of 357 MPa,and an EL of 9.7%.This remarkable strengthening effect is primarily attributed toβ-phase reinforcement,grain refinement strengthening,and strain hardening.
基金financially supported by National Key Research and Development Program of China(2022YFB3708400)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+1 种基金the Guangdong provincial key laboratory project(2023B1212060043)the Guangdong Academy of Science Fund(2020GDASYL-20200101001)。
文摘Achieving a balance between strength and ductility is of utmost importance for Magnesium matrix composites(MMCs).In this study,AZ31 sheets reinforced with 0.4,0.7,and 1.0 wt.%nano-TC4(Ti-6Al-4V)particles were prepared by stir casting coupled with hot extrusion process.In addition to analyzing the microstructure of the extruded composite sheets,the tensile properties were also investigated.The results showed that the incorporation of nano-TC4 particles led to a reduction in texture strength and a refinement of the grains.As a result of the formation of semicoherent orientation relations at the Ti Al/Mg and Ti3Al/Mg interfaces,strong interfacial bonding was established between the TC4 nanoparticles and the AZ31 matrix.Compared with the AZ31 sheet,the composite sheet with 0.7 wt.%nano-TC4 particles exhibited the best comprehensive tensile properties.The primary factors contributing to the improvement of mechanical properties were mismatch of coefficient of thermal expansion(CTE)between TC4 nanoparticles and AZ31 matrix,grain refinement,Orowan strengthening mechanism,and strong interfacial bonding.
基金the financial support from the National Key R&D Program of China(No.2022YFB3708400)National Natural Science Foundation of China(No.52171133,52225101)Basic and Applied Basic Research Foundation of Guangdong(No.2020B0301030006)。
文摘Magnesium matrix composites(MMCs)combine exceptional low density,high specific strength,and stiffness,positioning them as critical materials for aerospace,automotive,and electronics industries.This review highlights recent progress in the fabrication of Ti-Mg composites and analyzes the mechanisms behind their enhanced mechanical properties.A key focus is the interfacial deformation incompatibility between Ti and Mg phases,which generates strain gradients and promotes the accumulation of geometrically necessary dislocations(GNDs)at the interface.This process not only improves strain hardening and ductility but also reveals the need for advanced micromechanical models to capture the plastic behavior of both phases.The review critically examines the impact of different Mg matrix types(AZ,AM,VW series)and the role of interfacial product morphology and size on bonding and overall performance.Furthermore,Ti reinforcement endows the composites with superior wear resistance and thermal conductivity,indicating broad application potential.
基金supported by Guangdong Major Project of Basic and Applied Basic Research,No. 2020B0301030006。
文摘Laminated metal composites(LMCs) are a unique composite material and have great application prospects in automobiles, ships, aircraft,and other manufacturing industries. As lightweight materials, the Mg/Al LMCs are expected to combine the advantages of both Mg and Al alloys to broaden their application prospects. Roll-bonding is the most popular process for the fabrication of Mg/Al LMCs due to high production efficiency and good product quality stability. The roll-bonding process involves the deformation of the substrates and the formation of the interfacial diffusion layer. The latter will directly determine the interface bonding strength of Mg/Al LMCs. Bonding strength is very sensitive to the thickness of the reaction layer in the diffusion layer. When the thickness of the reaction layer exceeds 5 μm, the bonding strength decreases sharply. Therefore, controlling the thickness of the reaction layer is very important for the design of rolling parameters.The latest research also showed that the addition of intermediate layer metal and the construction of three-dimensional interfaces can further improve the interface bonding strength. How to apply these methods to roll-bonding is the focus of future research. Recently, a new rolling technique, corrugated roll/plat roll rolling+flat roll/flat roll rolling has been developed to fabricate Mg/Al LMCs. It can effectively promote the deformation of the hard layer and generate a wavy interface, resulting in the enhancement of the bonding quality and rolling quality.In the current review, the effects of rolling parameters and subsequent annealing on the interface structure of Mg/Al LMCs were elaborated in detail. The application of some special rolling techniques in the preparation of Mg/Al LMCs was also summarized. The latest research results on the relationship between interface structure and mechanical properties of Mg/Al LMCs were reviewed. Finally, further research directions in this field were proposed.
基金National Natural Science Foundation of China (52101123, 52171103)Guangdong Major Project of Basic and Applied Basic Research (2020B0301030006) for the support。
文摘Currently, many gratifying signs of progress have been made in magnesium(Mg) matrix composites(MMCs) by virtue of their high mechanical properties both at room and elevated temperatures. Although the commonly used reinforcements in MMCs are ceramic particles,they often provide improved yield and ultimate stresses by a significant loss in ductility. Therefore, hard metallic phases were introduced as alternative candidates for the manufacturing of MMCs, especially titanium(Ti). It has a high melting point, high Young’s modulus, high plasticity, low level of mutual solubility with Mg matrix, and closer thermal expansion coefficient to that of Mg metal than that of ceramic particles. It is highly preferable to provide both high ultimate stress and ductility in Mg matrix. However, many critical challenges for the fabrication of Ti-reinforced MMCs remain, such as Ti’s homogeneity, low recovery rate, and the optimization of interfacial bonding strength between Mg and Ti, etc. Meanwhile, different fabrication methods have various effects on the microstructures, mechanical properties, and the interfacial strength of Ti-reinforced MMCs. Hence, this review placed emphasis on the microstructural characteristics and mechanical properties of Ti-reinforced MMCs fabricated by different techniques. The influencing factors that govern the strengthening mechanisms were systematically compared and discussed. Future research trends, key issues, and prospects were also proposed to develop Ti-reinforced MMCs.
基金the financial supports from the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)the National Natural Science Foundation of China(Nos.52171103,52171133)+3 种基金the Natural Science Foundation of Chongqing(cstc2019jcyjmsxm X0234)the“111 Project”(B16007)by the Ministry of Educationthe Fundamental Research Funds for the Central Universities(No.2020CDJDPT001)Graduate Research and Innovation Foundation of Chongqing,China(No.CYB21001)。
文摘The compromise between strength and plasticity has greatly limited the potential application of particles reinforced magnesium matrix composites(MMCs).In this work,the Ti particles reinforced AZ31 magnesium(Mg)matrix composites achieved simultaneous improvement in strength,elongation and wear resistance.The Ti particles reinforced AZ31 composites were fabricated by ultrasonic-assisted stir casting with hot extrusion.The results showed that a strong interfacial bonding was obtained at Ti/Mg interface because of the formation of semicoherent orientation relationship of Ti Al/Mg,Ti Al/Al_(2)Ti and Al_(2)Ti/Mg interfaces.The as-extruded 6 wt.%Ti/AZ31 composite presented the best compressive mechanical properties and wear resistance with ultimate tensile strength,elongation and wear rate of 327 MPa,20.4%and 9.026×10^(-3)mm^(3)/m,obviously higher than those of AZ31 alloys.The enhanced mechanical properties were attributed to the grain refinement and strong interfacial bonding.The improved wear resistance was closely related to the increased hardness of composites and the formation of protective oxidation films.
基金supported by Guangdong Academy of Sciences(Nos.2021GDASYL-20210103102,2021GDASYL-20210103099)Guangdong Province Key Area R&D Program(No.2019B010940001)+1 种基金Guangzhou Science and Technology Project(No.202102020844)National Natural Science Foundation of China(No.12072110)。
文摘The coefficient of thermal expansion(CTE)mismatch between the reinforcement and the matrix results in thermal residual stresses and defects within metal-matrix composites(MMCs)upon cooling from the processing temperature to ambient temperature.The residual stresses and thermally induced defects play an important role in the mechanical properties of MMCs,it is critical to understand the mechanism of defect formation and evolution.This study provides atomistic simulations to reveal the generation of thermal residual stresses,dislocation and incomplete stacking fault tetrahedron(ISFT)during cooling in the idealized Cu/SiC composites.We found that dislocations are generated explosively in a certain temperature range during cooling,which results in a non-linear relationship between dislocation density and temperature.The combined effect of the stresses induced by CTE mismatch and the thermodynamic state of the metal leads to the rapid generation of dislocations.The Shockley partial and the highly stable stair rod are the two dominant dislocation structures.The immobile stair-rod dislocations and the highly stable ISFTs formed in the initial high temperature stage inhibit further development of plastic deformation.The present results provide new insights into the defect formation mechanism and the dislocation strengthening mechanism of MMCs caused by thermal mismatch between constituents.
基金supports from Guangdong Academy of Science Fund(2020GDASYL-20200101001)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+5 种基金the Natural Science Foundation of Guangdong Province(No.2020A1515011546)the Open Funding of Key Lab-oratory of New Processing Technology for Nonferrous Metal&Materials,Ministry of Education,Guilin University of Technology(Nos.20KF-7 and 20AA-8)the National Natural Science Foundation of China(U1764253,U2037601,51971044 and 52001037)the National Defense Basic Scientific Research program of China,the Qinghai Science and Technology Program(2018-GX-A1)the Chongqing Science and Technology Commission(cstc2017zdcy-zdzxX0006)Chongqing Scientific&Technological Talents Program(KJXX2017002).
文摘Curve extrusion processes,including symmetric curve extrusion(SCE)and asymmetric curve extrusion(ACE)processes,were proposed to fabricate Mg-3Al-1Zn(AZ31)alloy sheets with the aim of improving planar anisotropy.For comparison,traditional extrusion(TE)was conducted on producing AZ31 sheets.The dynamic recrystallization and flow behavior of AZ31 Mg alloy during extrusion were examined and analyzed,and the final microstructures and mechanical properties of AZ31 sheets were investigated.In comparison with the TE sheet,finer grain size,more uniform microstructure and weaker tilted basal tex-ture were achieved in the SCE and ACE sheets.Both the SCE and ACE sheets exhibited unique textures which basal poles tilted to extrusion direction(ED)and new transverse direction(TD)-tilted texture com-ponent was developed.The reasons were mainly ascribed to the introduction of additional flow velocity difference along TD during extrusion.Furthermore,the ACE sheet exhibited the lowest basal pole inten-sity,which was attributed to the introduction of extra asymmetric shear deformation during extrusion process.As a result,the ACE sheet showed the lowest yield strength and r-value,but highest elongation and n-value.Improving the planar anisotropy of AZ31 sheet was achieved by the ACE process.
基金Guangdong Academy of Science Fund(2020GDASYL-20200101001,2018GDASCX-0967,2019GDASYL-0302017 and 2019GDASYL-0502009)National Natural Science Foundation of China(51905111)+1 种基金Guangdong Science and Technology Project(2018dr005)Guangzhou Science and Technology Project(201704030094).
文摘In the present study,three types of bimetal composites,Al 6082 sleeve/Al 6082 core,Mg AZ31 sleeve/Mg AZ31 core and Al 6082 sleeve/Mg AZ31 core,were fabricated by drilling and assembling.The rule of mixtures(ROM)for the flow curves and yield strengths during compressive test were addressed.Our results show that the ROM can predict well the experimental flow curves and yield strengths of bimetal composites without bonding,irrespectively of the different strain hardening behavior between the two components.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research (2020B0301030006)the National Natural Science Foundation of China (52225101)+2 种基金the Scientific Research Foundation of Chongqing University of Technology (2020ZDZ006)the Science and Technology Research Program of the Chongqing Municipal Education Commission (KJZD-K202201108)the University Innovation Research Group of Chongqing (CXQT20023).
文摘A novel melting infiltration by ultrasonic vibration was investigated and applied to fabricate Ti6Al4V(TC4)lattice structure-reinforced Mg-10Gd-2Y-1Zn-xZr(refer to VW92 hereafter,x=0,0.5 wt%)alloy matrix composites.The edge-to-edge matching model indicates that the well-matching and possible orientation relationships(ORs)between theα-Mg andα-Ti,[10-10]_(α-Mg)//[11-23]_(α-Ti) in(0002)_(α-Mg)//(10-10)_(α-Ti) possesses the smallest misfit of 0.4%(f_(r)),and thus theα-Mg grains can nucleate on the TC4 lattice structure.Interfacial reaction occurred in the TC4/VW92+0.5 wt%Zr composites,and the reaction product was confirmed to be Al_(2)Zr_(3),AlZr_(2) andα-Ti(Zr)particles formed by continuous solution of Zr-Ti.Among the interfacial products,the AlZr_(2) phase is a brittle phase with high-volume fraction,which is not conducive to the load transfer.But generally speaking,theα-Ti(Zr)and theα-Mg tend to form a coherent interface,which is beneficial for improving the interfacial bonding strength of composites.
基金funded by the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2020B0301030006)。
文摘Adding Ti particles to magnesium alloy simultaneously enhances its strength and ductility.However,how these particles influence on Mg alloy’s corrosion performance is seldom reported.The corrosion behavior of AZ31-Ti composites containing titanium nanoparticles(1.5 and 5 wt%)and micron particles(10 wt%)prepared by powder metallurgical in 3.5 wt%NaCl solution was investigated.The results indicate that Ti particles serve as the primary location for the cathodic hydrogen reduction reaction,resulting in intense galvanic corrosion between the Ti and Mg matrix.Ti nanoparticles distributed at the interface of the original AZ31 powder were in a discontinuous mesh structure,thus failing to act as a barrier against corrosion.The corrosion products with the existence of numerous cracks gradually peel off during the corrosion process and cannot protect the matrix.The average corrosion rate P_(w) of AZ31,AZ31-1.5%Ti,AZ31-5%Ti,and AZ31-10%Ti after 7 days of immersion is 27.55,105.65,283.67,and 99.35 mm/y,respectively.Therefore,AZ31-Ti composites can be considered as potential candidates for degradable fracturing tools.Otherwise,it is recommended to improve their corrosion resistance through surface treatment.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research (No.2020B0301030006)the National Natural Science Foundation of China (No.52225101)+1 种基金the Graduate Research and Innovation Foundation of Chongqing,China (Grant No.CYB21001)the GDAS'Project of Science and Technology Development (No.2020GDASYL-20200101001).
文摘The ageing behavior of as-extruded Ti_(P)/VW94 composites was investigated.The peak hardness of the composites increases compared to the matrix alloy and the 5%Ti_(P)/VW94 composite presents the highest peak hardness of 148.7 HV after aging for about 50 h.However,the hardness increments first decrease and then slightly increase with increasing Ti particle content due to the introduction of high-density dislocations by Ti particles.
基金This work was financially supported by the National Key Research and development Program(2021YFB3701000)National Science Foundation of China(No.52071036,U2037601)+1 种基金the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)the Independent Research Project of State Key Laboratory of Mechanical Transmissions(SKLMT-ZZKT-2022Z01,SKLMT-ZZKT-2022M12).
文摘Generally,edge crack of rolled magnesium alloy sheets initiates in the RD(rolling direction)-ND(normal direction)plane and then propagate in the RD-TD(transverse direction)plane.Hence,the Mg-2Zn-1.5Mn(ZM21)alloy sheets with and without crack notch were designed to carry out in-situ tensile experiments under 150℃(the same temperature of rolling),with the aim to understand their crack propagation mechanism.The scanning electron microscopy(SEM)and electron backscattered diffraction(EBSD)techniques were utilized to reveal microstructural evolution in real time at designated displacements.The results show that the prismatic slip,basal slip,and extension twining play synergistic role in coordinating strain during the tensile process in ZM21 alloy sheet at 150℃.In both tensile samples with and without crack notch,localized strain is mainly concentrated at relatively fine grain area and the grain boundaries or triple junctions of the grains with large basal Schmid factor(SF)difference,which eventually leads to severe surface roughening and subsequent crack initiation.Compared with the sample without crack notch,the pre-cracked sample exhibits severer deformation at the crack tip due to strain concentration.Strain gradient distribution is observed at the crack tip region in the pre-cracked sample.The crack propagation path of the sample with pre-crack is identified and the underlying mechanism is also discussed.
