Mg-Gd-Y-Mn合金挤压及时效过程中的组织与力学性能

Microstructure and mechanical properties of Mg-Gd-Y-Mn alloy during extrusion and aging process

利用金相显微镜、扫描电镜、透射电镜和Instron材料试验机研究了Mg-9.05Gd-5.11Y-0.43Mn(wt%)合金热挤压及随后200℃等温时效过程中的组织演变与力学性能。结果表明:该合金铸锭晶粒粗大,热挤压发生动态再结晶使合金的晶粒尺寸减小;实验合金在200℃下时效具有明显的时效硬化效果;片状相沿棱柱面的大量析出是产生峰值时效硬化的主要原因,对合金强度提高起了很大的作用;该合金在室温及300℃下的拉伸性能明显优于WE54合金。

The microstructure evolution in Mg-9.4Gd-5.1Y-0.43Mn （wt%） alloy and its mechanical properties during extrusion and following isothermalaging at 200℃ was investigated using optical microscope （OM）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and tensile test. The results show that grains of the alloy at as-cast state are large, and hot extrusion can enormously decrease the grain size due to dynamic recrystallization （DRX）. A significant age-hardening phenomenon is observed when the extruded rods are aged at 200℃, which is mainly caused by large amount of plate-shaped phase precipitation along prismatic face. Tension property of the alloy is much better than that of WE54 alloy at room temperature and 300℃ .