固态回收法制备Mg-Zn-Y-Zr合金的微观组织和力学性能

采用冷压法压实Mg-Zn-Y-Zr合金碎屑,在不同温度和不同挤压比下进行热挤压。结果表明：在低于320℃时挤压,微观组织由大量再结晶晶粒和少量未再结晶晶粒组成,合金具有较高的强度和较低的韧性;当挤压温度升高到360℃时,发生完全再结晶,微观组织由等轴晶组成,合金具有较低的强度和较高的韧性;当挤压温度升高到420℃时,微观组织由粗大的等轴晶组成,导致了合金的力学性能下降;当挤压比从8增加到16时,晶粒明显细化,力学性能显著提高,然而,随着挤压比的进一步增加,屈服强度和极限抗拉强度升高幅度不大。

Microstructure and mechanical properties of Mg-Zn-Y-Zr alloy prepared by solid state recycling

Machined chips of Mg-Zn-Y-Zr alloy were consolidated by cold pressing and then hot extrusion under various processing temperatures and extrusion ratios. The results show that the microstructure of the chip-extruded alloy is marked by a large number of recrystallized grains and some unrecrystallized grains, which results in high strength but low ductility at temperatures below 320 ℃. With increasing processing temperature up to 360 ℃, entirely recrystallized and equiaxed grains are obtained. Mg-Zn-Y-Zr alloy with low strength but high ductility is obtained compared with the alloy processed at low temperature. At 420℃, coarse and equiaxed grains are formed, which results in the drastic decrease of mechanical properties. With increasing extrusion ratio from 8 to 16, the grain refinement is more obvious and the mechanical properties at room temperature are improved effectively. However, the yield strength and ultimate tensile strength are improved a little with further increasing extrusion ratio.