摘要
为了研究镁合金在高温、高应变速率下的变形行为及失效机制，采用分离式Hopkinson压杆在应变速率为1600—4500S^-1、温度为27—150℃范围内，对真空压铸AM60B镁合金进行了动态压缩实验，并采用金相显微镜和扫描电子显微镜对压缩后的组织进行了观察．结果表明：在所测试的应变范围内，随着应变率的提高，应力-应变曲线均呈现上升趋势，且最大应变也随之增加，表现出正应变率强化效应．在150℃时真空压铸AM60B镁合金变形能力最好；50℃时断裂强度最高．真空压铸AM60B镁合金在高温及高应变率下的断裂方式为以解理断裂为主并伴有韧性断裂的混合断裂方式．当变形温度低于150℃时，真空压铸AM60B镁合金在高应变率压缩下的变形机制主要是滑移．
In order to investigate the deformation behavior and failure mechanism of magnesium alloy at high temperature and high strain rate, the dynamic compression tests for the vacuum die casting AM60B magnesium alloy were carried out with the split Hopkinson pressure bar at the strain rates from 1 600 s^-1 to 4 500 s^-1 and at temperatures from 27℃ to 150℃. The microstructure of specimens after compression was observed with both optical microscope and scanning electron microscope （SEM）. The results show that within the testing strain range, the stress-strain curves show a rising trend and the maximum strain also increases with increasing the strain rate, where a positive strain rate strengthening effect is noted. The vacuum die casting AM60B magnesium alloy has the best deformability at 150℃, and exhibits the highest fracture strength at 50℃. At high temperatures and high strain rates, the fracture mode of vacuum die casting AM60B magnesium alloy is the mixed cleavage and ductile fracture, and the former is the dominant fracture mode. When the deformation temperature is lower than 150℃, the main deformation mechanism of vacuum die casting AM60B magnesium alloy during the compression at high stain rates is slip.
出处
《沈阳工业大学学报》
EI
CAS
北大核心
2013年第5期515-519,共5页
Journal of Shenyang University of Technology
基金
国家科技支撑计划资助项目(2011BAE22B05)
