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研究了等温热处理对AZ91D+Ce镁合金半固态组织的影响,获得了较理想的球状或类球状晶粒组织。结果表明,在等温热处理的过程中,加入稀土Ce会阻碍原子向固相粒子聚集和结合,抑制固相颗粒的长大,形成细小圆整的半固态组织。随等温热处理温度的升高,原子活动能力增强,熔化速度加快,液相量增加,固相颗粒尺寸先减小后增大。在等温初始阶段,熔化对初生固相颗粒尺寸起决定作用,使得颗粒尺寸减小。但是,随等温时间的进一步增加,由于合并粗化和Ostwald熟化的作用,固相颗粒开始长大。
The effect of isothermal heat treatment on the semi-solid microstructure of AZ91D + Ce magnesium alloy was studied and the ideal spherical or spheroidal crystal structure was obtained. The results show that during the isothermal heat treatment, the addition of rare earth Ce hinders the aggregation and bonding of atoms to the solid particles, inhibits the growth of solid particles and forms a fine semi-solid structure. With the increase of isothermal heat treatment temperature, atomic activity increases, the melting speed increases, the amount of liquid phase increases, and the size of solid phase particles decreases first and then increases. In the initial isothermal phase, melting plays a decisive role in the size of the primary solid phase particles, resulting in a reduction in particle size. However, with further increases in isothermal time, the solid particles begin to grow due to coarsening and Ostwald ripening.