(哈尔滨理工大学 材料科学与工程学院，哈尔滨 150040)
摘 要: 采用多道次固相合成AZ91D镁合金屑和Mg-Nd中间合金屑，研究了固相合成过程中β-Mg17Al12相和中间合金屑的破碎机理及分散均匀性。结果表明:在多道次固相合成过程中，中间合金屑逐渐破碎，Nd元素溶入晶粒内部，形成固溶强化；以球团状颗粒在晶界处均匀分布，形成第二相粒子强化；粗大的β-Mg17Al12相被破碎，削弱了对基体的割裂影响；破碎的β-Mg17Al12相和中间合金颗粒促进了动态再结晶的发生，形成细晶强化，力学性能明显提高。AZ91D-Nd镁合金的抗拉强度达到323MPa，比铸态时提高了29.2%，伸长率达到7.2%，与铸态的相当。
关键字: 固相合成；AZ91D；Mg-Nd中间合金；显微组织；力学性能
（School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China）
Abstract:AZ91D alloy chips and Mg-Nd master alloy chips were fabricated by multi-pass solid phase synthesis. The homogenization and breaking mechanism of β-Mg17Al12 phase and master alloy chips were analyzed. The results show that Mg-Nd master alloy chips are broken. Nd element dissolves inside the grain and solid solution strengthening is formed. The granular particles were distributed in the grain boundary, which produces the precipitation strengthening. The coarse β-Mg17Al12 phases, which deterioratesthe matrix, are broken. The broken β-Mg17Al12 phase and granular particles accelerate the dynamic recrystallization, refine the grain and improve the mechanical properties. The ultimate tensile strength of AZ91D-Nd alloy is 323 MPa, which is higher than that of as-cast AZ91D alloy. The elongation of AZ91D-Nd alloy is 7.2%, which is similar to that of as-castAZ91D alloy.
Key words: solid phase synthesis; AZ91D; Mg-Nd master alloy; microstructure; mechanical property
