Cr添加对NbMoZr系高熵合金力学性能与微观组织的影响  

Effect of Cr addition on mechanical properties and microstructure of NbMoZr high entropy alloys

作　　者：王涛 时洁 潘虎成 商洪宇 滕常青 张伟 吴璐[2] WANG Tao;SHI Jie;PAN Hucheng;SHANG Hongyu;TENG Changqing;ZHANG Wei;WU Lu(Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education),College of Materials Science and Engineering,Northeastern University,Shenyang 110819,Liaoning China;The First Sub-Institute,Nuclear Power Institute of China,Chengdu 610041,Sichuan China)

机构地区：[1]东北大学材料科学与工程学院材料各向异性与织构教育部重点实验室,辽宁沈阳110819 [2]中国核动力研究设计院第一研究所,四川成都610041

出　　处：《中国铸造装备与技术》2024年第3期74-81,共8页China Foundry Machinery & Technology

基　　金：国家自然科学基金委资助项目(U2067218、U2167213、U2241235);四川省科技厅资助项目(21MZGC0400,2022JDJQ0021);中国核工业集团有限公司青年英才菁英项目(CNNC-2021-31);反应堆燃料与材料国家重点实验室资助项目(6142A06190510);中央高校基本业务费项目(N2202020)。

摘　　要：采用电弧熔炼法成功制备了Nb_(50)Mo_(30)Zr_(20)及(Nb_(50)Mo_(30)Zr_(20))_(100-x)Cr_(x)(x=5、10、15,对应Cr5、Cr10及Cr15)合金,并系统研究了Cr含量对相结构、微观组织与力学性能的影响规律。研究结果表明,Cr元素的添加使NbMoZr合金由单一BCC结构相组织转变为富Mo、Nb的BCC基体相与富Zr、Cr、Nb的Laves相组成的双相组织,同时二次枝晶壁间距也逐渐减小。X射线衍射(XRD)和透射电子显微镜(TEM)分析表明,Laves相对应于FCC结构的Cr_2(Nb,Zr)相。因此,随着Cr含量的增加,压缩屈服强度逐渐从NbMoZr合金的1288 MPa提升至Cr15合金的1924 MPa,Laves相诱导的第二相强化以及枝晶细化导致的细晶强化是强度提升的主要机制。对比三种含Cr合金,发现Cr10合金表现出最优的强塑性匹配,屈服强度1690MPa,塑性应变9.0%,有望成为弥散性核燃料金属基体的有利候选材料之一。In this study,Nb_(50)Mo_(30)Zr_(20)and (Nb_(50)Mo_(30)Zr_(20))_(100-x)Cr_(x)(x=5,10,15,corresponding to Cr5,Cr10,and Cr15)alloys have been successfully prepared by arc melting method,and the effects of Cr content on phase structure,microstructure and mechanical properties have been systematically investigated.The results show that the addition of Cr changes the phase organization of NbMoZr alloys from a single BCC structure to a dual-phase organization consisting of Mo-and Nb-rich BCC matrix phases and Zr-,Cr-,and Nb-rich Laves phases,and the secondary dendritic wall spacing decreases gradually.x-ray difrac-tion(XRD)and transmission electron microscope(TEM)analyses show that the Laves phase corresponds to the FCC structure of the Cr_(2)(Cr10 and Cr15)alloy.structure of the Cr_(2)(Nb,Zr)phase.Therefore,the compressive yield strength gradually increased from 1288 MPa for NbMoZr alloy to 1924 MPa for Cr15 alloy with the increase of Cr content,and the second-phase strengthening induced by the Laves phase as well as fine-grain strengthening due to dendrite refinement were the main mechanisms for the strength enhancement.Comparing the three Cr-containing alloys,it is found that the Cr10 alloy exhibits the optimal strength-plasticity match with a yield strength of 1690 MPa and a plastic strain of 9.0%,which is expected to be one of the favorable candidates for dispersive nuclear fuel metal matrix.

关 键 词：难熔高熵合金 力学性能 LAVES相 相结构 强化机制 

分 类 号：TG139[一般工业技术—材料科学与工程]