Grain growth directly influences the plasticity and strength of Mg alloys.As the grain size decreases from the microscale to the nanoscale,the plasticity of Mg alloys continually increases,whereas the strength first i...Grain growth directly influences the plasticity and strength of Mg alloys.As the grain size decreases from the microscale to the nanoscale,the plasticity of Mg alloys continually increases,whereas the strength first increases and later decreases.These trends are observed because the plastic deformation mechanism changes from dislocation–twinning dominance to grain boundary dominance.In this study,the factors influencing grain growth,such as the temperature of plastic deformation/annealing,second-phase particles and solute atoms,are examined to aid effective control of the grain size.Additionally,the mechanisms of grain growth,typically induced by strain and thermal activation,are clarified.Strain-induced grain boundary migration is attributable to the difference in the strain energy stored in adjacent grains with high-density dislocations.Heat-induced grain boundary migration is driven by the difference in the energy of the grain boundary/subgrain boundary and boundary curvature.Abnormal grain growth can be induced by anisotropy of the strain energy,anisotropy of the grain boundary mobility,depinning of the second phase and high misorientation gradient.展开更多
Obtaining a highly synergistic mechanical property between joint and base metal(BM)in aluminum(Al)alloy is a chronic problem.In this work,shear bonding technology is applied to a commercial 6061 Al alloy.The results s...Obtaining a highly synergistic mechanical property between joint and base metal(BM)in aluminum(Al)alloy is a chronic problem.In this work,shear bonding technology is applied to a commercial 6061 Al alloy.The results show that a flat and uniform joint interface is obtained.The joint presents a highly synergistic mechanical property compared with BM,whether after shear bonding or heat treatment.The joint coefficient reaches 95.6%after shear bonding and exceeds 100%after heat treatment,which is better than the traditional connection method of aluminum alloy.The high joint coefficient mainly originates from the well-linked joint and gradient grain structure.The gradient grain structure is beneficial to activate more slip systems to coordinate plastic deformation.Although the fine-grained structure is sacrificed after heat treatment,higher strength and joint coefficient are obtained due to the higher work hardening.This newly developed method has a large potential for application to the infinite rolling of Al alloy sheets and can also be used for Al alloy connection in automobile,aerospace,rail transportation,and other fields.The findings in this work can provide essential theoretical support and application reference for the shear connection of Al alloy.展开更多
基金supported by Innovation Research Group of Universities in Chongqing(CXQT21030)Chongqing Talents:Exceptional Young Talents Project(CQYC201905100)Chongqing Youth Expert Studio,Hong Kong Scholars Program。
文摘Grain growth directly influences the plasticity and strength of Mg alloys.As the grain size decreases from the microscale to the nanoscale,the plasticity of Mg alloys continually increases,whereas the strength first increases and later decreases.These trends are observed because the plastic deformation mechanism changes from dislocation–twinning dominance to grain boundary dominance.In this study,the factors influencing grain growth,such as the temperature of plastic deformation/annealing,second-phase particles and solute atoms,are examined to aid effective control of the grain size.Additionally,the mechanisms of grain growth,typically induced by strain and thermal activation,are clarified.Strain-induced grain boundary migration is attributable to the difference in the strain energy stored in adjacent grains with high-density dislocations.Heat-induced grain boundary migration is driven by the difference in the energy of the grain boundary/subgrain boundary and boundary curvature.Abnormal grain growth can be induced by anisotropy of the strain energy,anisotropy of the grain boundary mobility,depinning of the second phase and high misorientation gradient.
基金supported by the Innovation research group of universities in Chongqing(no.CXQT21030)Chongqing Talents:Exceptional Young Talents Project(no.CQYC201905100)。
文摘Obtaining a highly synergistic mechanical property between joint and base metal(BM)in aluminum(Al)alloy is a chronic problem.In this work,shear bonding technology is applied to a commercial 6061 Al alloy.The results show that a flat and uniform joint interface is obtained.The joint presents a highly synergistic mechanical property compared with BM,whether after shear bonding or heat treatment.The joint coefficient reaches 95.6%after shear bonding and exceeds 100%after heat treatment,which is better than the traditional connection method of aluminum alloy.The high joint coefficient mainly originates from the well-linked joint and gradient grain structure.The gradient grain structure is beneficial to activate more slip systems to coordinate plastic deformation.Although the fine-grained structure is sacrificed after heat treatment,higher strength and joint coefficient are obtained due to the higher work hardening.This newly developed method has a large potential for application to the infinite rolling of Al alloy sheets and can also be used for Al alloy connection in automobile,aerospace,rail transportation,and other fields.The findings in this work can provide essential theoretical support and application reference for the shear connection of Al alloy.
