高应变速率下载荷方向对镁合金力学性能的影响  

Influence of loading direction on mechanical properties of magnesium alloy at high strain rate

作　　者：毛萍莉[1] 李小川[1] 王志[1] 刘正[1] 

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110870

出　　处：《沈阳工业大学学报》2011年第5期516-519,530,共5页Journal of Shenyang University of Technology

基　　金：国家973计划资助项目(2007CB613705);辽宁省教育厅创新团队资助项目(2009T073)

摘　　要：为了研究高应变速率下AZ31B镁合金动态力学行为各向异性,采用分离式霍普金森压杆(SHPB)对沿挤压方向(ED)、法向(ND)及横向(TD)加工的AZ31B镁合金在应变速率为1 058～2500 s-1范围内进行冲击压缩实验,并采用扫描电镜观察压缩断口形貌.结果表明:高应变速率下AZ31B镁合金沿ED方向和ND方向有明显的应变强化现象,而沿TD方向应力对应变速率不敏感;随应变速率的增加,不同载荷方向屈服强度与最大应力值的差值变化程度有所不同,其中沿ND方向差值变化最大,沿TD方向差值变化最小;通过观察扫描断口形貌发现,在高应变速率下AZ31B镁合金在不同载荷方向下的断裂方式均为解理断裂.In order to investigate the anisotropy of dynamic mechanical behavior at high strain rate for AZ31B magnesium alloy,the impact compressive tests for the AZ31B magnesium alloy processed respectively along the extrusion direction（ED）,normal direction（ND） and transverse direction（TD） were carried out with split Hopkinson pressure bar in the strain rate range of 1058 to 2500s-1.In addition,the morphologies of compressive fracture surface were observed by scanning electron microscopy（SEM）.The results show that the AZ31B magnesium alloy along both extrusion direction（ED） and normal direction（ND） exhibits significant strain hardening.However,the stress of the AZ31B magnesium alloy along the transverse direction（TD） is not sensitive to strain rate.With increasing the strain rate,the change in the differential values between yield strength and maximum stress is different for the AZ31B magnesium alloy along different loading direction.The differential values show the maximum change along the normal direction（ND） and the minimum change along the transverse direction（TD）.The fracture morphology observation reveals that at high strain rate,the fracture modes of the AZ31B magnesium alloy along different loading direction are all cleavage fracture.

关 键 词：镁合金 高应变速率 载荷方向 分离式霍普金森压杆 应变强化 屈服强度 最大应力值 解理断裂 

分 类 号：TG115.5[金属学及工艺—物理冶金]