Growth twinning behavior of cast Mg-Zn-Cu-Zr alloys
(1. School of Mechanical Engineering, University of South China, Hengyang 421001, China;
2. School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China)
2. School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China)
Abstract: The morphology and orientation of the growth twins formed in the cast Mg-Zn-Cu-Zr alloys aged at 100 °C were characterized using optical microscopy and transmission electron microscopy. It was found that twins were invisible in the as-cast or solutionized Mg-Zn-Cu-Zr alloys while twins were exclusively formed in the aged condition. The twinning behavior was significantly affected by two factors, namely, the Zn content and the heat treatment process. A possible formation mechanism of such growth twins was discussed using the viewpoint of vacancy.
Key words: Mg-Zn-Cu-Zr alloy; Mg alloys; twinning; heat treatment; vacancy