重熔过程的组织演变
(中国科学院 金属研究所， 沈阳 110016)
摘 要: 研究利用低压脉冲电场技术制备的AZ91D镁合金在部分重熔过程中的组织演变，考察加热温度和保温时间对不同脉冲电压制备的AZ91D合金初生相形态和尺寸的影响。 结果表明： 经低压脉冲电场处理后，将AZ91D镁合金进行部分重熔可得到非枝晶的半固态合金， 随坯料制备的脉冲电压增加， 重熔时初生相变得圆整且尺寸减小，但制备坯料的脉冲电压过高， 重熔时初生相尺寸有所增加； 脉冲电场处理后的AZ91D镁合金坯料经适当的部分重熔处理可获得具备触变过程所需要的组织状态。
关键字: AZ91D镁合金； 低压脉冲电场； 半固态合金；部分重熔
（Institute of Metal Research, Chinese Academy of Sciences,
Shenyang 110016, China）
Abstract: The non-dendritic semi-solid magnesium alloy AZ91D is prepared by reheating the AZ91D alloy treated by low-voltage electric current pulse (LVECP) technique. The microstructure evolution of magnesium alloy AZ91D prepared by LVECP during partial remelting, and the effects of heating temperature and holding time on the partial remelted microstructure of the alloy treated with different pulse voltages were investigated. The results show that when heating temperature and holding time are constant, the primary grains become small with the increment of pulse voltage. If the pulse voltage is too high, the primary grains will be coarse. The alloy treated by LVECP and partially remelted has fine microstructure suitable for thixoforming.
Key words: magnesium alloy AZ91D; low-voltage electric current pulse; semi-solid alloy; partial remelting
