Homogenization heat treatment of Mg-7.68Gd-4.88Y-1.32Nd-0.63Al-0.05Zr alloy

• Published in: Journal of rare earths Vol. 32; no. 5; pp. 445 - 450
• Main Author: 张国栋 李兴刚 马鸣龙 李永军 石国梁 袁家伟 张奎
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2014
• Subjects: Dissolution; Grain boundaries; hardness; Heat treatment; Homogenization; Homogenizing; Intermetallic compounds; Magnesium base alloys; Mg-Gd-Y-Nd-Al alloy; Optical microscopy; Rare earth metals; rare earths; second phase; 力学性能; 后热处理; 均匀化热处理; 扫描电子显微镜; 显微组织; 硬度测定; 铸态合金; 镁合金; hardness; homogenization; second phase; Mg-Gd-Y-Nd-Al alloy; rare earths
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/S1002-0721(14)60092-2

The microstructures and mechanical properties of the Mg-7.68Gd-4.88Y-1.32Nd-0.63A1-0.05Zr magnesium alloy were investigated both in the as-cast condition and after homogenization heat treatment from 535 to 555 ℃ in the time range 0-48 h by op- tical microscopy, scanning electron microscopy and hardness measurement. The as-cast alloy consisted of ct-Mg matrix, Mgs（Y0.5Gd0.5） phase which is a eutectic phase, strip of Al2（Y0.6Gd0.4） phase, little A13Zr and Mg（Y3Gd） phase. With the increasing of homogenization temperature and time, the Mgs（Y0.5Gd0.5） phase was completely dissolved into the matrix. The Al2（Y0.6Gd0.4） phase was almost not dissolved which impeded grain boundaries motion making the grain size almost not changed in the process of ho- mogenization. The optimum homogenization condition was 545 ℃/16 h. The tensile strength increased, yield strength decreased and the plasticity improved obviously after 545 ℃/16 h homogenization treatment.