Al-4Cu-Mg合金半固态重熔时的组织演变

文章研究了Al-4Cu-Mg合金半固态重熔过程中加热温度和保温时间对微观组织形貌和α晶粒尺寸的影响,并对组织演化机制进行了探讨。实验结果表明,当加热温度较低或保温时间较短时,晶粒尺寸小且均匀性差。由于液相分数少,α晶粒之间粘连严重。随着加热温度的升高或保温时间的延长,α晶粒发生了长大和圆整化。对于Al-4Cu-Mg合金来说,合适的半固态重熔参数为:加热温度为540℃~580℃;保温时间小于10min。在半固态重熔过程中,α晶粒的合并长大和Ostwald长大是其微观组织演化的主要机制,两种晶粒长大机制在重熔过程中所起的作用受液相体积分数的影响。

Microstructural evolution of the semi-solid Al-4Cu-Mg alloy during partial remelting

Effects of the isothermal temperature and holding time on the microstructural morphology and grain size have been investigated during partial remelting of the semisolid Al-4Cu-Mg alloy.The mechanism of microstructural evolution has been discussed in the paper.The experimental results show that the α grains coarsen gradually and become more globular with an increase of the isothermal temperature and holding time.For the Al-4Cu-Mg alloy,the optimal process parameters include the isothermal temperature range from 540℃ to 580℃ and below holding time of 10min.The coalescence of grains and Ostwald ripening theory are two main mechanisms of the grain coarsening during partial remelting,which plays an important role at different liquid fraction.