AM80-0.2Sr-1.5Ca镁合金高温压缩过程动态再结晶模拟  

Simulation of the Dynamic Recrystallization of AM80-0.2Sr-1.5Ca Magnesium Alloy during Hot Compression Deformation

作　　者：李落星[1,2] 何凤亿[1,2] 刘筱 周佳[1,2] 

机构地区：[1]湖南大学汽车车身先进设计制造国家重点实验室 [2]湖南大学材料科学与工程学院,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2011年第12期46-51,共6页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51075132);湖南省杰出青年基金资助项目(09JJ1007);教育部长江学者与创新团队发展计划资助项目(531105050037);湖南大学汽车车身先进设计制造国家重点实验室自主课题资助项目(61075005)

摘　　要：在Gleeble-1500热压缩实验机上对AM80-0.2Sr-1.5Ca镁合金进行高温压缩实验，得到了该合金在温度为300~450 ℃、应变速率为0.01~1 s-1条件下的流变应力曲线.结合改进的Laasraoui-Jonas（L-J）位错密度模型和Kock-Mecking（K-M）位错密度模型，获得AM80-0.2Sr-1.5Ca镁合金在改进的L-J位错密度模型中的应变硬化参数和应变软化参数，建立该合金的动态再结晶模型.利用DEFORM-3D软件，实现了对AM80-0.2Sr-1.5Ca镁合金在450 ℃热压缩实验时微观组织演变和位错密度变化过程的有限元模拟，并与实际热压缩实验微观组织进行对比.研究结果表明：在相同的温度和应变量下，应变速率较低时，AM80-0.2Sr-1.5Ca镁合金组织粗大且晶粒分布不均，随着应变速率增大，再结晶组织细小均匀模拟与实验结果一致，说明求解的应变硬化参数和应变软化参数准确，所建立的动态再结晶模型能准确预测该合金高温压缩过程动态再结晶过程.Hot compression tests of a new type of AM80-0.2Sr-1.5Ca magnesium alloy were performed on Gleeble-1 500 at a strain rate of 0.01~1 s-1 and a deformation temperature of 300~450 ℃. The true stress-true strain curves and the strain hardening rate were obtained. The parameters of the modified L-J microstructure model, including the hardening parameter and recovery parameter, were calculated by combining the L-J model with K-M model. The evolution of the microstructure and dislocation density of the AM80-0.2Sr-1.5Ca magnesium alloy during the hot compression at 450 ℃ were simulated by using DEFORM-3D software. The results have shown that the recrystallized grains are larger and distribute non-uniformly when the strain rates are low, and the recrystallized grain size decreases with the increase of strain rate. The simulation results agree well with the experiments, which prove the accuracy of the L-J modeling for predicting the DRX process during hot compression.

关 键 词：L—J微观组织模型 微观组织模拟 动态再结晶 位错密度 

分 类 号：TG146.2[一般工业技术—材料科学与工程]