摘要
对铸态AZ31镁合金进行了轧制温度为320~460℃、平均应变速率为1.9~7.8 s-1的中高应变速率轧制,研究了不同轧制工艺参数下AZ31镁合金板的边裂长度及形核、扩展和止裂机制。结果表明,随着轧制温度的升高,边裂平均长度整体呈下降趋势。随着平均应变速率的增加,轧制边裂得到改善。边裂扩展路径上孪晶和再结晶是主要的微观结构。在中等应变速率轧制中,再结晶不完全,粗晶区和细晶区均存在。在高应变速率轧制中,再结晶速率快,再结晶完全,因此微观组织以细晶区为主。粗晶区的边裂由孪晶诱导产生并在边裂扩展路径上产生大量的孪晶,在边裂尖端,孪晶再结晶的产生抑制了边裂的扩展。细晶区的边裂是由孔洞形核、长大和合并引起的,大量细小的再结晶晶粒阻碍了边裂扩展,且晶粒越细小,边裂扩展受阻程度越大。
The medium-high strain rate rolling of as-cast AZ31 magnesium alloy was carried out at the rolling temperature of 320-460℃and average strain rate of 1.9-7.8 s-1.Edge crack length and the mechanism of nucleation,propagation and edge crack inhibition with different rolling process parameters were investigated.The results show that with the increase of rolling temperature,the average length of edge crack decreases.With the increase of average strain rate,the rolling cracks are improved.Twin and recrystallization are the main microstructures in the edge crack propagation path.In the medium strain rate rolling,the recrystallization is incomplete,both coarse grain area and fine grain exist.In high strain rate rolling,the recrystallization rate is fast,and the recrystallization is complete,therefore,the fine grain is the main microstructure.The edge crack in the coarse grain area is induced by twin and a large number of twins are generated in the edge crack propagation path.Twin induced recrystallization at the edge crack tip inhibits the crack propagation.The edge crack in the fine grain area is generated by nucleation,propagation and coalescence of voids.A large number of fine recrystallizetion grains impede the edge crack propagation and the smaller the grains are,the greater the inhibition of edge crack propagation is.
作者
邢秀伟
黄晨
刘阳
朱必武
杨伟成
肖罡
XING Xiu-wei;HUANG Chen;LIU Yang;ZHU Bi-wu;YANG Wei-cheng;XIAO Gang(College of Materials Science and Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;College of Mechanical and Electrical Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;College of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;Jiangxi KMAX Industrial Co.,Ltd.,Nanchang 330001,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2023年第5期66-72,共7页
Journal of Plasticity Engineering
基金
国家自然科学基金资助项目(51905166
52071139
52075159)
湖南省自然科学基金资助项目(2022JJ30019)
湖南省教育厅优秀青年基金资助项目(21B0470)。
关键词
AZ31镁合金
中高应变速率轧制
边裂
孪晶
再结晶
AZ31 magnesium alloy
medium-high strain rate rolling
edge crack
twin
recrystallization
