大型Mg-Gd-Y铸件成分、热处理优化和性能评价

Optimization of Composition and Heat Treatment and Performance Evaluation of Large Mg-Gd-Y Castings

针对大型砂型铸造镁合金铸件晶粒粗大、室温塑性较差的问题,模拟大型铸件的慢冷条件,通过成分优化、微观组织分析、热处理优化的方法研究了大型Mg-Gd-Y镁合金铸件室温强韧化的最优工艺参数。结果表明:Mg-6Gd-3Y-0. 5Zr(GW63K)具有良好的综合性能,GW63K的最佳固溶处理参数为475℃/7 h+495℃/3 h,最佳时效处理参数为200℃/80 h,本体室温抗拉、屈服强度和延伸率依次达到了334. 5 MPa、201. 0MPa和6. 2%,具有良好的室温强韧性。

Large sand casting magnesium alloys were prone to coarse grains,resulting in poor elongation at room temperature. In order to solve the above problems,the slow cooling conditions of large castings was simulated and the optimum process parameters of room temperature strengthening and toughening of large Mg-Gd-Y magnesium alloy castings were studied by composition optimization,microstructure analysis and heat treatment optimization. It is found that Mg-6Gd-3Y-0. 5Zr(GW63K) has good comprehensive performance,the optimum solution treatment parameters for GW63K are 475 ℃/7 h+495 ℃/3h,and the optimum aging treatment parameters are 200 ℃/80 h,and the average tensile,yield strength and elongation at room temperature are 334. 5 MPa,201. 0 MPa 和 6. 2%,respectively. This study provides a reference for the application of Mg-Gd-Y alloys on large castings.