A New Analytical Model for the Flow Stress of Twin-roll Casting Magnesium Sheet at Elevated Temperatures  

作　　者：Zhimin Liu,Shuming Xing ,Peiwei Bao,Nan Li,Shuqing Yao and Milan Zhang School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong University,Beijing 100044,China 

出　　处：《Journal of Materials Science & Technology》2010年第5期461-466,共6页材料科学技术（英文版）

基　　金：supported by the Beijing Natural Science Foundation, China (No. 3093024);the Beijing Jiaotong University Science Foundation, China (No.2007XM035)

摘　　要：To evaluate the flow stress of the twin-roll casting magnesium sheet in high temperature forming processes,a new analytical model was proposed by analyzing stress-strain curves measured under various temperatures and strain rates.The model can be parameterized to reflect the volume fraction of semi-sold grain and sold grains undergoing twinning.By applying the new model,the result showed that the simulated stress-strain curves fit the experiment data very well.Such curve fitting can be employed for any magnesium sheet when the deformation conditions are known.Microstructure evolution indicated that it affected the stress-strain curves directly.The mechanisms of dynamic recrystallization（DRX） depended on the operating deformation mechanisms,which changed with temperatures.And the volume fraction and grain size of DRX changed with the Zener-Hollomon parameter and temperatures.To evaluate the flow stress of the twin-roll casting magnesium sheet in high temperature forming processes,a new analytical model was proposed by analyzing stress-strain curves measured under various temperatures and strain rates.The model can be parameterized to reflect the volume fraction of semi-sold grain and sold grains undergoing twinning.By applying the new model,the result showed that the simulated stress-strain curves fit the experiment data very well.Such curve fitting can be employed for any magnesium sheet when the deformation conditions are known.Microstructure evolution indicated that it affected the stress-strain curves directly.The mechanisms of dynamic recrystallization（DRX） depended on the operating deformation mechanisms,which changed with temperatures.And the volume fraction and grain size of DRX changed with the Zener-Hollomon parameter and temperatures.

关 键 词：Twin-roll casting Semi-sold grains TWINNING 

分 类 号：TG292[金属学及工艺—铸造]