(哈爾濱理工大學(xué) 材料科學(xué)與工程學(xué)院，哈爾濱 150040)
摘 要: 采用多道次固相合成AZ91D鎂合金屑和Mg-Nd中間合金屑，研究了固相合成過程中β-Mg17Al12相和中間合金屑的破碎機(jī)理及分散均勻性。結(jié)果表明:在多道次固相合成過程中，中間合金屑逐漸破碎，Nd元素溶入晶粒內(nèi)部，形成固溶強(qiáng)化；以球團(tuán)狀顆粒在晶界處均勻分布，形成第二相粒子強(qiáng)化；粗大的β-Mg17Al12相被破碎，削弱了對(duì)基體的割裂影響；破碎的β-Mg17Al12相和中間合金顆粒促進(jìn)了動(dòng)態(tài)再結(jié)晶的發(fā)生，形成細(xì)晶強(qiáng)化，力學(xué)性能明顯提高。AZ91D-Nd鎂合金的抗拉強(qiáng)度達(dá)到323MPa，比鑄態(tài)時(shí)提高了29.2%，伸長率達(dá)到7.2%，與鑄態(tài)的相當(dāng)。
關(guān)鍵字: 固相合成；AZ91D；Mg-Nd中間合金；顯微組織；力學(xué)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
