Mg alloys with a combination of high strength and excellent ductility are increasingly required for structural applications.This study investigates the influence of advanced processing techniques on the mechanical pro...Mg alloys with a combination of high strength and excellent ductility are increasingly required for structural applications.This study investigates the influence of advanced processing techniques on the mechanical properties and microstructural evolution of Mg-Gd-Y-Zn-Zr alloys.Utilizing a combination of double extrusion and stepwise hot rolling followed by aging treatments,significant enhancements in the mechanical performance of these alloys are demonstrated.The processing techniques applied lead to notable refinement in grain-size and modifications in the microstructure,including the transformation of LPSO phases from 18R to 24R and the dispersion of β phase particles.These microstructural transformations contribute to a substantial increase in yield-strength,ultimate-tensile-strength,and ductility.Furthermore,findings reveal that these improvements are also supported by alterations in material texture,which influence dislocation dynamics as indicated by changes in Kernel Average Misorientation(KAM)values.The combined effect of grain boundary(GB)strengthening,phase distribution,and texture modification elucidates the observed mechanical enhancements.This research provides valuable insights into the design and optimization of Mg-Gd-Y-Zn-Zr alloys for critical applications in aerospace and automotive industries where high strength and ductility are paramount.展开更多
The study aimed to shed light on the post deformation and damage behavior of an extruded Mg-Zn-Zr alloy under a ballistic impact.The results revealed that the initial microstructure consisted of both{0001}basal and{10...The study aimed to shed light on the post deformation and damage behavior of an extruded Mg-Zn-Zr alloy under a ballistic impact.The results revealed that the initial microstructure consisted of both{0001}basal and{1010}prismatic fiber texture.After impact,adiabatic shear bands,pronounce different twinning in big grains,,<c>,and<c+a>types of dislocations,and grain refinement through twinning induce recrystallization accommodated the strain,and absorbed∼65.7%of the energy during impact carried by a soft steel projectile.Interestingly,the deformation behavior at the top broad sides of the crater was entirely different.The weak basal texture was changed to a strong prismatic texture,which was further proved by typical sigmoidal compressive stress-strain curves.A revised model for the development of the ultra-fine grains adjacent to the crater has been proposed.The microhardness and yield strength was∼33%and∼40%higher and chiefly ascribed to strain hardening in ultra-fine grained near the surface of the perforation path.The exit of the perforation path was severely damaged and forms onion-shaped concentric rings which were comprised of melted zones,dimples,and cracks.Based on the all interesting findings,this study can be a clue for the development of the lightweight Mg alloy for military and aerospace applications.展开更多
From the mechanistic point of view,magnesium alloys are lightweight materials and are receiving increasing attention in the past several years in various fields.Prof.Liang Zhen from Harbin Institute of Technology,Chin...From the mechanistic point of view,magnesium alloys are lightweight materials and are receiving increasing attention in the past several years in various fields.Prof.Liang Zhen from Harbin Institute of Technology,China and the United State military are showing keen interest in the development of magnesium alloys as ballistic resistant material.However,their use is still limited owing to low ductility,low formability,and average mechanical properties.The magnesium alloys components must withstand the shockwave under hypervelocity ballistic impact.The ballistic testing can produce gradient variations of the strain and stress-energy away from the crater,and useful for the development of these alloys in the military and aerospace industry.Therefore,the present review article shed light on the post deformation analysis of the Mg alloys subjected to the different projectiles under ballistic impact,and the underlying mechanisms were discussed.In the end,some important issues regarding the ballistic impact and further studies in this field were proposed.展开更多
Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055(SF-7055)Al alloy were investigated.Results show that with the increase of the reduction from 20%to 80%,the grain of cryogenic ...Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055(SF-7055)Al alloy were investigated.Results show that with the increase of the reduction from 20%to 80%,the grain of cryogenic rolled SF-7055 Al alloy is elongated to form a fiber texture.Numerous proliferating dislocations in the microstructure accumulate into dislocation walls and cells,and eventually form subgrains.These subgrain boundaries divide the original grain,thereby reducing the grain size.Under severe deformation conditions,they even enable the formation of nanograins.Meanwhile,the Cu-rich precipitates in the matrix are also broken and refined under the action of large rolling stress.In the process of cryogenic rolling,the tensile strength and hardness of SF-7055 Al alloy gradually increase,while the plasticity decreases.Moreover,the fracture morphology of cryogenic rolled SF-7055 Al alloy gradually transforms to the ductile and quasi-cleavage hybrid fracture characteristics with increased reduction.展开更多
This study systematically engineers a series of Mg-1.0Zn-xCa-ySn alloys(ZXT-series)by systematically varying Sn/Ca atomic ratios(1:4 in ZXT4,1:8 in ZXT8,and 1:16 in ZXT16)to investigate its impact on microstructural e...This study systematically engineers a series of Mg-1.0Zn-xCa-ySn alloys(ZXT-series)by systematically varying Sn/Ca atomic ratios(1:4 in ZXT4,1:8 in ZXT8,and 1:16 in ZXT16)to investigate its impact on microstructural evolution,mechanical properties,and corrosion behavior in Hank’s solution.Through systematic investigation,the complex effects of the Sn/Ca atomic ratio on the microstructural evolution were elucidated,and the strengthening mechanisms of the ZXT series alloys were quantitatively analyzed and compared.Consequently,due to the finest recrystallized grains,ZXT16 alloy achieved a peak yield strength of 264 MPa.Notably,the ZXT4 alloy(Sn/Ca ratio 1:4)demonstrated the most balanced overall performance,with a yield strength of~233 MPa,elongation~18.0%and a low degradation rate of~0.208 mm/year.This enhanced corrosion resistance in ZXT4 is attributed to its refined grain structure,minimized micro-galvanic activity from CaMgSn precipitates(Volta potential difference VPD≈195 mV with the matrix),and the formation of a dense,stratified,multicomponent protective corrosion product layer composed of a Zn-rich(ZnO/Zn(OH)_(2))inner barrier,an MgO/Mg(OH)_(2)/SnO/SnO_(2)intermediate matrix,and an outer Ca_(3)(PO_(4))_(2)deposition via accelerated nucleation kinetics.A triphasic corrosion progression mechanism further elucidated these observations.This work establishes crucial processing-microstructure-property-corrosion relationships and presents strategic Sn/Ca ratio optimization as a robust pathway for developing advanced Mg-Zn-Ca-Sn biomaterials.展开更多
基金financially supported by the financial supports from the National Natural Science Foundation of China(Grant No.52027805).
文摘Mg alloys with a combination of high strength and excellent ductility are increasingly required for structural applications.This study investigates the influence of advanced processing techniques on the mechanical properties and microstructural evolution of Mg-Gd-Y-Zn-Zr alloys.Utilizing a combination of double extrusion and stepwise hot rolling followed by aging treatments,significant enhancements in the mechanical performance of these alloys are demonstrated.The processing techniques applied lead to notable refinement in grain-size and modifications in the microstructure,including the transformation of LPSO phases from 18R to 24R and the dispersion of β phase particles.These microstructural transformations contribute to a substantial increase in yield-strength,ultimate-tensile-strength,and ductility.Furthermore,findings reveal that these improvements are also supported by alterations in material texture,which influence dislocation dynamics as indicated by changes in Kernel Average Misorientation(KAM)values.The combined effect of grain boundary(GB)strengthening,phase distribution,and texture modification elucidates the observed mechanical enhancements.This research provides valuable insights into the design and optimization of Mg-Gd-Y-Zn-Zr alloys for critical applications in aerospace and automotive industries where high strength and ductility are paramount.
基金This project was financially supported by the National Natural Science Foundation of China(No.51702015)。
文摘The study aimed to shed light on the post deformation and damage behavior of an extruded Mg-Zn-Zr alloy under a ballistic impact.The results revealed that the initial microstructure consisted of both{0001}basal and{1010}prismatic fiber texture.After impact,adiabatic shear bands,pronounce different twinning in big grains,,<c>,and<c+a>types of dislocations,and grain refinement through twinning induce recrystallization accommodated the strain,and absorbed∼65.7%of the energy during impact carried by a soft steel projectile.Interestingly,the deformation behavior at the top broad sides of the crater was entirely different.The weak basal texture was changed to a strong prismatic texture,which was further proved by typical sigmoidal compressive stress-strain curves.A revised model for the development of the ultra-fine grains adjacent to the crater has been proposed.The microhardness and yield strength was∼33%and∼40%higher and chiefly ascribed to strain hardening in ultra-fine grained near the surface of the perforation path.The exit of the perforation path was severely damaged and forms onion-shaped concentric rings which were comprised of melted zones,dimples,and cracks.Based on the all interesting findings,this study can be a clue for the development of the lightweight Mg alloy for military and aerospace applications.
基金financially supported by the National Natural Science Foundation of China.(Grant no.51702015)。
文摘From the mechanistic point of view,magnesium alloys are lightweight materials and are receiving increasing attention in the past several years in various fields.Prof.Liang Zhen from Harbin Institute of Technology,China and the United State military are showing keen interest in the development of magnesium alloys as ballistic resistant material.However,their use is still limited owing to low ductility,low formability,and average mechanical properties.The magnesium alloys components must withstand the shockwave under hypervelocity ballistic impact.The ballistic testing can produce gradient variations of the strain and stress-energy away from the crater,and useful for the development of these alloys in the military and aerospace industry.Therefore,the present review article shed light on the post deformation analysis of the Mg alloys subjected to the different projectiles under ballistic impact,and the underlying mechanisms were discussed.In the end,some important issues regarding the ballistic impact and further studies in this field were proposed.
基金financially and technically supported by the National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact,Beijing Institute of Technology,China(No.WDZC2024-1)。
文摘Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055(SF-7055)Al alloy were investigated.Results show that with the increase of the reduction from 20%to 80%,the grain of cryogenic rolled SF-7055 Al alloy is elongated to form a fiber texture.Numerous proliferating dislocations in the microstructure accumulate into dislocation walls and cells,and eventually form subgrains.These subgrain boundaries divide the original grain,thereby reducing the grain size.Under severe deformation conditions,they even enable the formation of nanograins.Meanwhile,the Cu-rich precipitates in the matrix are also broken and refined under the action of large rolling stress.In the process of cryogenic rolling,the tensile strength and hardness of SF-7055 Al alloy gradually increase,while the plasticity decreases.Moreover,the fracture morphology of cryogenic rolled SF-7055 Al alloy gradually transforms to the ductile and quasi-cleavage hybrid fracture characteristics with increased reduction.
基金support for this work is provided by the National Natural Science Foundation of China(Grant Nos.52027805,52204381)the National High Level Hospital Clinical Research Funding(BJ-2023-085)the National Key Research and Development Plan(2022YFC3601905,2022YFC3601900).
文摘This study systematically engineers a series of Mg-1.0Zn-xCa-ySn alloys(ZXT-series)by systematically varying Sn/Ca atomic ratios(1:4 in ZXT4,1:8 in ZXT8,and 1:16 in ZXT16)to investigate its impact on microstructural evolution,mechanical properties,and corrosion behavior in Hank’s solution.Through systematic investigation,the complex effects of the Sn/Ca atomic ratio on the microstructural evolution were elucidated,and the strengthening mechanisms of the ZXT series alloys were quantitatively analyzed and compared.Consequently,due to the finest recrystallized grains,ZXT16 alloy achieved a peak yield strength of 264 MPa.Notably,the ZXT4 alloy(Sn/Ca ratio 1:4)demonstrated the most balanced overall performance,with a yield strength of~233 MPa,elongation~18.0%and a low degradation rate of~0.208 mm/year.This enhanced corrosion resistance in ZXT4 is attributed to its refined grain structure,minimized micro-galvanic activity from CaMgSn precipitates(Volta potential difference VPD≈195 mV with the matrix),and the formation of a dense,stratified,multicomponent protective corrosion product layer composed of a Zn-rich(ZnO/Zn(OH)_(2))inner barrier,an MgO/Mg(OH)_(2)/SnO/SnO_(2)intermediate matrix,and an outer Ca_(3)(PO_(4))_(2)deposition via accelerated nucleation kinetics.A triphasic corrosion progression mechanism further elucidated these observations.This work establishes crucial processing-microstructure-property-corrosion relationships and presents strategic Sn/Ca ratio optimization as a robust pathway for developing advanced Mg-Zn-Ca-Sn biomaterials.
