选区激光熔融制备Cu-Cr-Nb-Ce合金组织与性能的高温稳定性  

High-temperature stability of microstructure and properties of Cu-Cr-Nb-Ce alloy fabricated by selective laser melting

作　　者：艾永康 刘祖铭[1] 张亚洲 叶书鹏 李建 AI Yongkang;LIU Zuming;ZHANG Yazhou;YE Shupeng;LI jian(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2022年第5期478-487,共10页Materials Science and Engineering of Powder Metallurgy

基　　金：国家重点研发计划资助项目(2021YFB3701100);金属材料磨损控制与成型技术国家地方联合工程研究中心开放基金资助项目。

摘　　要：采用选区激光熔融(selective laser melting, SLM)法制备Cu-Cr-Nb-Ce合金,通过对合金进行1 000℃高温热处理,研究Cu-Cr-Nb-Ce合金显微组织、力学性能和导电性能的高温稳定性。结果表明,在SLM成形件的XY面(垂直于建造方向),基体组织由熔池道中心的长柱状晶和沿熔池道边界分布的细小等轴晶组成,两者交错分布,平均晶粒尺寸为28.3μm,第二相为在基体中弥散分布的纳米级Cr2Nb相。SLM成形件经1 000℃高温热处理10、50和100h后,晶粒的整体形貌无明显变化,但平均晶粒尺寸分别增加8.5%、18.7%和27.2%;Cr2Nb相的平均尺寸从29.5 nm分别长大到348.6、524.9和589.4 nm,最大尺寸达1~3μm,并且在晶界分布更密集;合金的维氏硬度(HV)明显下降,从126分别降至84、79和75。经10 h热处理,电导率从18.5%IACS显著提高到54.6%IACS,延长热处理时间,则电导率不再明显提高。Cu-Cr-Nb-Ce alloy was fabricated by selective laser melting(SLM). The high-temperature stability of microstructure, mechanical properity and electrical conductivity of Cu-Cr-Nb-Ce alloy was studied by high-temperature heat treatment at 1 000 ℃. The results show that the matrix mocrostructure of the XY plane(perpendicular to the build direction) of the as-SLMed Cu-Cr-Nb-Ce alloy is composed of long columnar grains in the center of the molten pool and fine equiaxed grains distributed along the boundary of the molten pool. The two kinds of grains are staggered and the average grain size is 28.3 μm. The second phase are the nanoscale Cr2Nb phases dispersed in the matrix. After heat treatment at 1 000 ℃ for 10, 50 and 100 h, the overall morphology of the grains does not change obviously, but the grains grow and the average size of grain increases by 8.5%, 18.7% and 27.2%, respectively;The average size Cr2Nb phase grows from 29.5 nm to 348.6 nm, 524.9 nm and 589.4 nm respectively, and the maximum size reaches 1-3 μm. In addition, Cr2Nb phases in heat-treated specimens are more densely along the grain boundary. The hardness(HV) of the alloy decreases significantly from 126 to 84, 79 and 75 respectively;while the electrical conductivity increases significantly from 18.5%IACS to 54.6%IACS after heat treatment for 10 h, whereas no significant progress is observed with extension of the heat treatment time.

关 键 词：Cu-Cr-Nb-Ce合金 选区激光熔融 显微组织 高温稳定性 性能 

分 类 号：TG146.1[一般工业技术—材料科学与工程]