重熔過程的組織演變
(中國科學(xué)院 金屬研究所， 沈陽 110016)
摘 要: 研究利用低壓脈沖電場技術(shù)制備的AZ91D鎂合金在部分重熔過程中的組織演變，考察加熱溫度和保溫時間對不同脈沖電壓制備的AZ91D合金初生相形態(tài)和尺寸的影響。 結(jié)果表明： 經(jīng)低壓脈沖電場處理后，將AZ91D鎂合金進(jìn)行部分重熔可得到非枝晶的半固態(tài)合金， 隨坯料制備的脈沖電壓增加， 重熔時初生相變得圓整且尺寸減小，但制備坯料的脈沖電壓過高， 重熔時初生相尺寸有所增加； 脈沖電場處理后的AZ91D鎂合金坯料經(jīng)適當(dāng)?shù)牟糠种厝厶幚砜色@得具備觸變過程所需要的組織狀態(tài)。
關(guān)鍵字: AZ91D鎂合金； 低壓脈沖電場； 半固態(tài)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
