Effects of semi-solid isothermal process parameters on microstructure of Mg-Gd alloy

• Published in: Transactions of Nonferrous Metals Society of China Vol. 20; no. B07; pp. 402 - 406
• Main Author: 苏桂花 曹占义 刘勇兵 王玉慧 张亮 程丽任
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2010; Key Laboratory of Automobile Materials,Ministry of Education,Department of Materials Science and Engineering,Jilin University,Changchun 130025,China
• Subjects: Alloy development; Extrusion; Isothermal processes; isothermal treatment; magnesium alloy; Magnesium base alloys; Mg-Gd alloy; Microstructure; rare earth; Semi-solid processing; semisolid; Semisolids; strain-induced melt activation; Volume fraction; 半固态浆料; 合金组织; 微观结构; 最佳工艺参数; 相体积分数; 等温时间; 镁合金; rare earth; magnesium alloy; semisolid; isothermal treatment; strain-induced melt activation; Mg-Gd alloy
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(10)60506-7

The effects of semi-solid isothermal process parameters on the microstructure evolution of Mg-Gd rare earth alloy produced by strain-induced melt activation（SIMA）were investigated.The formation mechanism of the particles in the process of the isothermal treatment was also discussed.The results show that the microstructure of the as-cast alloy consists ofα-Mg solid solution, Mg5RE and Mg24RE5（Gd,Y,Nd）phase.After being extruded with an extrusion ratio of 14：1 at 380℃,the microstructure of Mg-Gd alloy changes from developed dendrites to near-equiaxed grains.The liquid volume fraction of the semisolid slurry gradually increases with elevating isothermal temperature or prolonging isothermal time during the partial remelting.To obtain an ideal semisolid slurry,the optimal process parameters for the Mg-Gd alloy should be 630℃for isothermal temperature and 30 min for the corresponding time,respectively,where the volume fraction of the liquid phase is 52%.