Cu添加对Mg-Bi合金铸态组织和沉淀硬化的影响  

Effects of Cu addition on as-cast microstructure and precipitation hardening of Mg-Bi alloy

作　　者：周菁菁 杨文朋[1,2] 陈亮 崔红保[1,2] 郭学锋[1,2] ZHOU Jing-jing;YANG Wen-peng;CHEN Liang;CUI Hong-bao;GUO Xue-feng(School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China;Henan International Joint Research Laboratory for High-Performance Light Metallic Materials and Numerical Simulations,Henan Polytechnic University,Jiaozuo 454000,China)

机构地区：[1]河南理工大学材料科学与工程学院,焦作454000 [2]河南理工大学河南省高性能轻金属材料及其数值模拟国际联合实验室,焦作454000

出　　处：《中国有色金属学报》2023年第3期689-701,共13页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51571086)。

摘　　要：制备Mg-5Bi-xCu(x=0,0.2,0.5,1.0,质量分数,%)合金铸锭,研究其铸态组织和沉淀硬化行为。结果表明:铸态Mg-Bi-Cu合金主要由α-Mg枝晶、Mg3Bi_(2)相、MgCu_(2)相和Mg_(2)Cu相组成,Mg_(3)Bi_(2)相和α-Mg基体的取向关系为(■)Mg_(3)Bi_(2)//(■)Mg、[■]Mg_(3)Bi_(2)//[■]Mg,Mg_(2)Cu相和Mg_(3)Bi_(2)相之间的取向关系为(■)Mg_(2)Cu//(■)Mg_(3)Bi_(2)、[■]Mg2Cu//[0001]Mg_(3)Bi_(2)。铸态合金硬度随Cu添加量提高先增大后减小,添加0.5%Cu时硬度最高,为(50.9±1.2)HV。固溶态Mg-5Bi-0.5Cu合金硬度为(49.8±0.9)HV。在175℃时效64 h后,硬度达到峰值(56.1±0.7)HV。时效硬度的提高主要是由于高密度Mg3Bi2相的沉淀强化作用,且由于Cu元素的添加,长杆状Mg3Bi2沉淀相转变为颗粒状和短棒状Mg_(3)Bi_(2)沉淀相。The Mg-5Bi-xCu(x=0,0.2,0.5,1.0,mass fraction,%)alloy ingots were prepared by conventional casting.The microstructures of as-cast alloys and precipitate hardening behavior were investigated.The results show that the as-cast Mg-Bi-Cu alloy is mainly composed ofα-Mg,Mg_(3)Bi_(2),MgCu_(2) and Mg_(2)Cu phases.The orientation relationships betweenα-Mg matrix and Mg_(3)Bi_(2) phase are(■)Mg_(3)Bi_(2)∥(■)Mg and[■]Mg_(3)Bi_(2)∥[■]Mg.The orientation relationships between Mg_(2)Cu phase and Mg_(3)Bi_(2) phase are(■)Mg_(2)Cu∥(■)Mg_(3)Bi_(2) and[■]Mg_(2)Cu∥[■]Mg_(3)Bi_(2).The hardness of the alloy increases firstly and then decreases with the increase of Cu addition amount,and the highest hardness of(50.9±1.2)HV is achieved in the alloy with 0.5%Cu.The hardness of Mg-5Bi-0.5Cu alloy after solid-solution treatment is(49.8±0.9)HV.After aging at 175℃for 64 h,the peak hardness of the alloy is(56.1±0.7)HV.The increase of aging hardness is attributed to the precipitation strengthening effect of high density Mg_(3)Bi_(2).Moreover,due to the addition of Cu element,the long rod-shaped Mg_(3)Bi_(2) precipitates transform to the granular and short rod-shaped precipitates.

关 键 词：Mg-Bi合金 合金化 显微组织 时效硬化 

分 类 号：TG146.2[一般工业技术—材料科学与工程]