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采用OM、SEM和XRD对Mg-5Gd-3Y-2Nd-0.5Zn-0.5Zr合金铸态和510℃均匀化处理过程中的微观组织变化进行了系统研究。结果表明:铸态合金的微观组织主要由α-Mg基体、晶界上灰黑色的不规则块状相、灰白色的骨骼状相和晶界附近细小的针状LPSO相组成;铸态合金的相结构为α-Mg、Mg3(RE,Zn)和Mg5(RE,Zn);510℃均匀化处理过程中,不但晶界上的共晶组织发生回溶,而且晶界附近的细小针状LPSO相也发生了回溶。均匀化处理48 h后,晶界上仍然存在少量共晶组织。
The microstructure changes of Mg-5Gd-3Y-2Nd-0.5Zn-0.5Zr alloy during as-cast and homogenization at 510 ℃ were systematically investigated by OM, SEM and XRD. The results show that the microstructure of as-cast alloy is mainly composed of α-Mg matrix, gray and black irregular massive phase, gray-white skeletal phase and fine needle-like LPSO phase near the grain boundary. (RE, Zn) and Mg5 (RE, Zn). When homogenized at 510 ℃, not only the eutectic structure of the grain boundary remelted but also the small acicular LPSO phase A dissolve also took place. After homogenizing for 48 h, a small amount of eutectic structure still exists on the grain boundary.