Effects of trace Cr on as-cast microstructure and microstructural evolution of semi-solid isothermal heat treatment ZC61 magnesium alloy

论文摘要

The content and kind of trace elements in magnesium alloys have important effects on their ascast and semi-solid microstructures. In this research work, effects of trace Cr on as-cast and semi-solid microstructures of ZC61 magnesium alloy were investigated by metal mold casting and semi-solid isothermal heat treatment. The results show that the addition of Cr can refine the α-Mg phase without generating a new phase, noticeably change the eutectic phase, and decrease the average size of solid particles at the same isothermal heat treatment conditions. Non-dendritic microstructures of all alloys are constituted of α1-Mg phases, α2-Mg phases and eutectic phases after water quenching. With isothermal temperature increased or holding time prolonged, the eutectic microstructure（α-Mg+MgZn2+CuMgZn） at the grain boundaries in as-cast alloy is melted preferentially and then turned into semi-solid non-dendritic microstructure by processes of initial coarsening, microstructure separation, spheroidizing and final coarsening. Especially when the ZC61-0.1 Cr alloy was treated at 585 ℃ for 30 min, the ideal non-dendritic microstructure can be obtained, and the corresponding solid particle size and shape factor were 37.5 μm and 1.33, respectively. The coarsening process of solid α-Mg phase at higher temperature or longer time, which is affected by both combining growth and Ostwald ripening mechanism, is refrained when Cr is added to the ZC61 alloy.

论文目录

• 1 Experimental procedures
• 2 Results and discussion
•   2.1 As-cast microstructures
•   2.2 Semi-solid microstructural evolution ofZC61-x Cr （x=0, 0.1, 0.2, 0.3） alloys
•     2.2.1 Effects of different Cr contents and is othermal temperatures on non-dendritic microstructural evolution of ZC61 alloy
•     2.2.2 Effects of different holding times on semi-solidmicrostructural evolution of ZC61-0.1Cr alloy
•     2.2.3 Semi-solid microstructural characterization
• 3 Conclusions

文章来源

类型: 期刊论文

作者: Xiao-feng Huang,Ya-jie Ma,Qiao-qiao Zhang,Lang-lang Wei,Jian-qiao Yang

来源: China Foundry 2019年01期

年度: 2019

分类: 工程科技Ⅰ辑

专业: 金属学及金属工艺

单位: State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology

基金: financially supported by the National Natural Science Foundations of China(51464032)

分类号: TG166.4;TG146.22

页码: 53-62

总页数: 10

文件大小: 2431K

下载量: 18