Effects of heat-treatment on microstructure of wrought magnesium alloy ZK60
(1.重庆市重庆科技学院材料科学与工程学院
2.重庆市重庆大学材料科学与工程学院
3.College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
4.College of Materials Science and Engineering, Chongqing Institute of Technology, Chongqing 400050, China)
2.重庆市重庆大学材料科学与工程学院
3.College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
4.College of Materials Science and Engineering, Chongqing Institute of Technology, Chongqing 400050, China)
Abstract: The microstructure of the as-cast, as-solution-treated and as-aged wrought magnesium alloy ZK60 was studied. The results indicate that the microstructure of the as-cast ZK60 alloy is mainly composed of network eutectic (α-Mg+MgZn) and divorced eutectic MgZn, which semi-continuously distribute along the grain boundaries or in the interdendritic area and almost dissolve into the matrix after solid solution treatment. The Laves phase MgZn2 is not sensitive to the heat treatment and seems to form at the early stage of solidification and keeps its size and shape till the aging stage. It is believed that the occurrence of the Laves phase in the ZK60 alloy would possibly contribute to the defects. Many new phases, including MgZn phase which is different from that forms during eutectic reaction, precipitate after aging treatment.
Key words: wrought magnesium alloy; ZK60; microstructure; alloy phase; MgZn2; eutectic