中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 12 December 2014 |
（1. National Engineering Research Center of Light Alloy Net Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. Department of Materials Science and Engineering, Norwegian University of Science and Technology,
Trondheim 7491, Norway;
3. Key State Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, Shanghai 200240, China;
4. Center for Advanced Materials, Qatar University, Doha POB 2713, Qatar）
Abstract:The microstructure, the content of compounds, mechanical properties and fracture behavior of high vacuum die casting Mg-8Gd-3Y-0.4Zr alloy (mass fraction, %) under T4 condition and T6 condition were investigated. The microstructure for the as-cast Mg-8Gd-3Y-0.4Zr alloy mainly consists of α-Mg and eutectic Mg24(Gd,Y)5 compound. After solution treatment, the eutectic compounds dissolve massively into the Mg matrix. The main composition of solution-treated alloys is supersaturated α-Mg and cuboid-shaped phase. The T4 heat treated samples have increasing cuboidal particles with the increase of heat treatment temperature, which turn out good mechanical properties. The optimum T4 heat treatment for high vacuum die cast Mg-8Gd-3Y-0.4Zr alloy is 475 °C, 2 h according to microstructure results. The optimum ultimate strength and elongation of solution-treated Mg-8Gd-3Y-0.4Zr alloy are 222.1 MPa and 15.4%, respectively. The tensile fracture mode of the as-cast, and T6 heat treated alloys is transgranular quasi-cleavage fracture.
Key words: Mg-8Gd-3Y-0.4Zr alloy; heat treatment; microstructure; mechanical property; fracture behavior
