浇注温度对Mg-6Al-1.2Y-0.9Nd合金组织及性能的影响

Effects of Pouring Temperature on Microstructures and Mechanical Properties of Mg-6Al-1.2Y-0.9Nd Alloys

研究了浇注温度(660～740℃)对Mg-6Al-1.2Y-0.9Nd合金的显微组织和力学性能的影响。结果表明,随着浇注温度升高,晶界鱼骨状的Mg17Al12相减少;稀土化合物Al2Y和Al2Nd相增加,并由细小、弥散转变为团状或柱状;浇注温度过高时合金中产生疏松及生成氧化物Al2O3,合金的拉伸强度和伸长率、密度首先升高,当温度超过680～700℃后,呈不断下降趋势。

The investigation was carried out on effects of pouring temperature on the microstructure and mechanical properties of as-cast Mg-6Al-1.2Y-0.9Nd alloy. The results show that with the increasing of pouring temperature （ 660-740 ℃ ）, the size and amount of the branched inter-granular Mg17Al12 phase decrease; while the size and amount of dispersed Al-RE （Al2Y, Al2Nd） particles increase; the micro-porosity and oxide of Al2O3 occur in the alloy when pouring temperature is too high. The tensile strength, elongation, density of alloys increases at first and then decreases when the pouring temperature over 680-700 ℃.