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研究触变成形AM60B镁合金在固溶处理过程中的组织演变及其热处理动力学。结果表明:触变成形AM60B镁合金在固溶处理过程中其组织演变可分为两个阶段,第一阶段为共晶β (Mg17Al12) 相的迅速溶解、溶质快速均匀化及晶粒粗化,第二阶段为初生颗粒及二次晶粒的正常长大阶段。在第一阶段,由于细小的β相快速溶入小的二次晶粒,造成该溶解过程较短,而溶质Al元素的均匀化则需要相对较长的时间,同时,组织形貌及颗粒尺寸有很大变化。在395 °C固溶时,第一阶段持续约1 h。与第一阶段相比第二阶段需要较长的时间,在本次实验条件下约60 h。第一阶段的快速均匀化使Al的浓度梯度在第二阶段大幅度减小,因此在该阶段组织变化并不明显。在第一阶段,初生相颗粒的长大模式满足幂函数关系,而二次晶粒则遵从传统的长大方程;然而,在第二阶段两者的长大方式相同。
The microstructure evolution and heat treatment kinetics of thixoformed AM60B magnesium alloy during solution treatment were studied. The results show that the microstructure evolution of the thixoformed AM60B magnesium alloy can be divided into two stages. The first stage is the rapid dissolution of eutectic β (Mg17Al12) phase, rapid homogenization of solute and coarsening of grains , The second stage is the normal growth phase of primary particles and secondary particles. In the first stage, the dissolution process is relatively short due to the small β phase rapidly dissolving into the small secondary grains, while the homogenization of the solute Al element takes relatively long time. Meanwhile, the morphology and particle size There is a big change. At 395 ° C, the first phase lasts about 1 h. Compared with the first phase of the second phase takes a longer time, in this experimental conditions about 60 h. The rapid homogenization of the first stage caused the concentration gradient of Al to decrease drastically in the second stage, so the microstructure change was not obvious at this stage. In the first stage, the growth model of primary particles satisfies the power function relationship, while the secondary one follows the traditional growth equation; however, both grow in the same way in the second phase.