(1. 重庆大学 材料科学与工程学院，重庆 400044；
2. 重庆大学 国家镁合金材料工程技术研究中心，重庆 400044)
摘 要: 研究超声处理对Mg-6Zn-0.5Y-2Sn合金显微组织及力学性能的影响。结果表明，超声处理对 Mg-6Zn- 0.5Y-2Sn合金显微组织及力学性能有显著影响。Mg-6Zn-0.5Y-2Sn合金是由α-Mg相、MgZn2相、MgSnY相、Mg2Sn相和少量I相组成。经超声处理后，I相基本消失，并且随着超声功率的提高，粗大的枝晶结构逐渐变成圆整的等轴晶，位于晶界附近粗大、半连续、不均匀分布的第二相逐渐变得细小、不连续、均匀且弥散分布。当超声功率达到700 W时，Mg-6Zn-0.5Y-2Sn合金的综合力学性能达到最佳。与未超声处理的镁合金相比，其屈服强度、极限抗拉强度和伸长率分别提高了28%、30% 和67%。
关键字: Mg-6Zn-0.5Y-2Sn合金；超声处理；显微组织:力学性能
（1. School of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China）
Abstract:The effects of the ultrasonic treatment on the microstructure and mechanical properties of Mg-6Zn-0.5Y-2Sn alloy were investigated. The results show that the ultrasonic treatment has significant effect on the microstructure and mechanical properties of Mg-6Zn-0.5Y-2Sn alloy. The phases in Mg-6Zn-0.5Y-2Sn alloy are α-Mg, MgZn2, MgSnY, Mg2Sn, and a small amount of I-phase. With the application of ultrasonic treatment, I-phase nearly disappears, and with increasing the ultrasonic treatment power, the coarse dendrites gradually change into roundish equiaxed grains. The second phases at the α-Mg boundaries transform from coarse, semicontinuous and non-uniform to fine, discontinuous, uniform and dispersive. When the ultrasonic treatment power is 700 W, the best comprehensive mechanical properties of Mg-6Zn-0.5Y-2Sn alloy are obtained. Compared with the untreated alloy, the 0.2% tensile yield strength, ultimate tensile strength and elongation are improved by 28%, 30% and 67%, respectively.
Key words: Mg-6Zn-0.5Y-2Sn alloy; ultrasonic treatment; microstructure; mechanical properties
