This paper addresses the microstructure evolution in the Zn-1.2Al-1.2Mg coating of press-hardened steel during heat treatment at temperatures ranging from 600 ℃ to 900 ℃.The presence of aluminum in the coating leads...This paper addresses the microstructure evolution in the Zn-1.2Al-1.2Mg coating of press-hardened steel during heat treatment at temperatures ranging from 600 ℃ to 900 ℃.The presence of aluminum in the coating leads to substantial variation in the chemical composition and microstructure within the heat-treated layer.As the heat treatment temperature increases, the original Fe_(2)Al_(5) barrier layer between the coating layer and steel substrate is progressively dissolved and replaced by the aggregates of a new(FeAl) phase.At higher heat treatment temperatures, the(FeAl) phase gradually migrates to the subsurface layer of the coating.Meanwhile, Zn/Fe interdiffusion induces Γ-Fe_(3)Zn_(10)-phase formation in the original coating layer and α-Fe(Zn) solid solution formation at the zinc-substrate interface.These microstructure features suppress the high-temperature oxidation and evaporation of Zn.展开更多
To improve the accuracy of the vehicle crashworthiness simulation,it is necessary as well as important to integrate the valid forming effects of key parts.It has been agreed by many that one-step simulation results sh...To improve the accuracy of the vehicle crashworthiness simulation,it is necessary as well as important to integrate the valid forming effects of key parts.It has been agreed by many that one-step simulation results should be used only as a qualitative trend of the part but not as an engineering result for further structural analysis,especially for a relatively complex part.The study shows that it is inaccurate to analyze the forming effects with one-step simulation based on the geometry of the final part through comparison with the incremental simulation and verification with the actual part,whether in thickness or in plastic strain.However,incremental simulation is very time consuming and infeasible in the early stage of vehicle design due to lacking of forming tools and process parameters.An engineering approach is proposed to meet the requirement of accuracy as well as the time efficiency,where one-step simulation is conducted based on the geometry of the transformed part instead of the final part.The geometry of the transformed part is generated by simple die design engineering and proves to offer much more accuracy than the one-step simulation based on the final part geometry.展开更多
文摘This paper addresses the microstructure evolution in the Zn-1.2Al-1.2Mg coating of press-hardened steel during heat treatment at temperatures ranging from 600 ℃ to 900 ℃.The presence of aluminum in the coating leads to substantial variation in the chemical composition and microstructure within the heat-treated layer.As the heat treatment temperature increases, the original Fe_(2)Al_(5) barrier layer between the coating layer and steel substrate is progressively dissolved and replaced by the aggregates of a new(FeAl) phase.At higher heat treatment temperatures, the(FeAl) phase gradually migrates to the subsurface layer of the coating.Meanwhile, Zn/Fe interdiffusion induces Γ-Fe_(3)Zn_(10)-phase formation in the original coating layer and α-Fe(Zn) solid solution formation at the zinc-substrate interface.These microstructure features suppress the high-temperature oxidation and evaporation of Zn.
基金supported from the National Natural Science Foundation of China (Grant No. 51005144)the Innovation Program of Shanghai Municipal Education Commission and Shanghai Automotive Industry Science and Technology Development Foundation (Grant No. 1009)
文摘To improve the accuracy of the vehicle crashworthiness simulation,it is necessary as well as important to integrate the valid forming effects of key parts.It has been agreed by many that one-step simulation results should be used only as a qualitative trend of the part but not as an engineering result for further structural analysis,especially for a relatively complex part.The study shows that it is inaccurate to analyze the forming effects with one-step simulation based on the geometry of the final part through comparison with the incremental simulation and verification with the actual part,whether in thickness or in plastic strain.However,incremental simulation is very time consuming and infeasible in the early stage of vehicle design due to lacking of forming tools and process parameters.An engineering approach is proposed to meet the requirement of accuracy as well as the time efficiency,where one-step simulation is conducted based on the geometry of the transformed part instead of the final part.The geometry of the transformed part is generated by simple die design engineering and proves to offer much more accuracy than the one-step simulation based on the final part geometry.
