The role of coarse second-phase particles in the microstructural evolution and mechanical properties of as-extruded Mg-Gd-Y-Ag-Zr alloys was investigated. Results show that the volume fraction of coarse β particles was enhanced by the addition of Ag (0.5 and 1.0) (wt.%) in the Mg-10.5 Gd-5 Y-0.5 Zr (wt.%) alloy. These particles have a face-centered cubic structure phase. In addition to Gd and Y, Ag is also partitioned into particles in the Ag-containing alloys. β particles can promote the dynamic recrystallization via particle-simulated nucleation and effectively suppress grain growth by pinning effects, which are responsible for the grain refinement. With the increase of volume fraction of β particles, the texture and dislocation features have not been changed. Since the coarse β particles can greatly lead to the reduction of grain size, the grain boundary strengthening in Ag-containing alloys with high volume fraction of particles contributes to the significantly improvement of the tensile yield strength. The coupled effect of the increase in the coarse β particle fraction and the reduction in grain size causes a slight decrease in elongation for the Ag-containing alloy.

研究了粗大的第二相颗粒在挤压态Mg-Gd-Y-Ag-Zr合金的微观组织演变和力学性能中的作用。结果表明，通过在Mg-10.5 Gd-5 Y-0.5 Zr（wt。％）合金中添加Ag（0.5和1.0）（wt。％），可以提高粗大β颗粒的体积分数。这些颗粒具有面心立方结构相。除Gd和Y外，Ag还被分为含Ag合金中的颗粒。β颗粒可通过颗粒模拟成核促进动态再结晶，并通过钉扎效应有效抑制晶粒长大，而钉扎效应是晶粒细化的原因。随着β粒子体积分数的增加，织构和位错特征没有改变。由于粗大的β颗粒会极大地导致晶粒尺寸减小，颗粒体积分数高的含银合金的晶界强化有助于显着提高抗拉屈服强度。β粗颗粒分数的增加和晶粒尺寸的减小的耦合效应导致含Ag合金的延伸率略有下降。