铸造CrCoNi中熵合金碳化物析出行为及力学性能  

Carbide Precipitation Behavior and Mechanical Properties of the Casting CrCoNi Medium-entropy Alloy

作　　者：缪良田 杜辉 胡光武 Miao Liangtian;Du Hui;Hu Guangwu(Key Laboratory of Metallurgical Equipment and Control Technology,Ministry of Education,Wuhan University of Science and Technology;Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering,Wuhan University of Science and Technology;State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology)

机构地区：[1]武汉科技大学冶金装备及其控制教育部重点实验室,武汉430081 [2]武汉科技大学机械传动与制造工程湖北省重点实验室 [3]华中科技大学材料成形与模具技术国家重点实验室

出　　处：《特种铸造及有色合金》2021年第6期738-742,共5页Special Casting & Nonferrous Alloys

基　　金：材料成形与模具技术国家重点实验室开放基金资助项目(P2019-005)。

摘　　要：针对铸造CrCoNi中熵合金室温强度低的问题,添加了3%(摩尔分数,下同)的Mo和0.5%的C,研究了碳化物的析出行为及其对合金的相结构、微观组织、硬度和室温压缩性能的影响。制备工艺采用传统的电弧熔炼、滴铸、固溶(1250℃×6 h)和时效(950℃×1 h)处理,制备的铸造合金中析出了弥散分布的M_(23)C_(6)碳化物。细小的碳化物均匀分布在晶粒内部,粗大的碳化物分布在晶界。经碳化物强化后,CrCoNi合金的硬度(HV)由157增加到250,屈服强度由223 MPa提高到342 MPa,强化效果主要归因于碳化物的析出强化。In order to enhance the room-temperature strength of a casting CrCoNi medium-entropy alloy,3%Mo and 0.5%C were added into the alloy.The carbide precipitation behavior and its effects on phase structure,microstructure,hardness and compressive properties at room temperature of the CrCoNi alloy were investigated.Traditional processes including arc melting,drop-casting,solid solution treatment at 1250℃for 6 h and aging at 950℃for 1 h were adopted.The dispersed carbides are precipitated from the alloy after aging.Fine carbides are evenly distributed in the intragranular regions,and coarse carbides are distributed on the grain boundaries.The hardness of the(CrCoNi)_(96.5)Mo_(3)C_(0.5) alloy is increased from 157 HV of the CrCoNi alloy to 250 HV,and the yield strength at room temperature is increased from 223 MPa to 342 MPa,which is attributed to the precipitation strengthening of carbide.

关 键 词：中熵合金 碳化物 微观组织 硬度 压缩性能 

分 类 号：TG139[一般工业技术—材料科学与工程] TG146.412[金属学及工艺—合金]