Deformation Behavior and Failure Analysis of Wrought Magnesium During Twin Rolling Casting and Hot Compression-猫眼课题宝

变形镁双轧铸造热压缩变形行为及失效分析

DOI：

10.1115/1.4004489

发表时间：

2012-10

期刊：

Journal of Engineering Materials and Technology-Transactions of the ASME

影响因子：

1.2

通讯作者：

中科院分区：

材料科学4区

文献类型：

作者：

Shouren WANG;Suk Bong Kang;JaeHyung Cho;Peiquan GUO;Liying YANG

研究了AZ 41 M（Mg-Al-Zn-Mn-Ca）和ZK 60（Mg-Zn-Zr）变形镁合金在双辊铸轧和热压缩变形条件下不同温度和应变速率下的流变应力。探讨了它们的变形行为和破坏机理。利用光学显微镜和电子背散射衍射技术分析了组织演变过程。结果表明，AZ 41 M和ZK 60在相同条件下具有不同的应变-应力曲线。加工硬化导致在剪切带内或剪切带周围产生裂纹。剪切带中的再结晶、等轴和细化晶粒是回复和再结晶的结果，晶粒细化导致局部加工硬化和裂尖驱动力降低。应力集中在剪切带中，导致裂纹萌生和扩展。铸造缺陷引起的裂纹核是另一种失效模式。随着应变的增加，位错在亚晶水平上发生重排，小角度晶界不断向大角度晶界演化。

The flow stress of AZ41M (Mg-Al-Zn-Mn-Ca) and ZK 60 (Mg-Zn-Zr) wrought magnesium alloys under the deformation conditions of twin rolling casting and hot compression at different temperature and strain rates was studied. Deformation behavior and failure mechanism of them were discussed. Microstructure evolutions were analyzed by optical microstructure and electron backscatter diffraction technique. The results have indicated that AZ41M and ZK 60 have different strain-stress curve under the same conditions. Working hardening results in occurrence of cracks in or around the shear bands. The recrystallized, equiaxed, and fined grains in shear bands attribute to recovery and recrystallization, grains refinement causes local working hardening as well as decreases of crack tip driving forces. Stress concentrated in shear bands causes crack initiation and propagation. Nucleus of cracks due to casting defects is another failure mode. With the increase of strain, dislocation rearranged in subgrain level while the low angle grain boundaries continuously evolved into high angle grain boundaries.