激光熔覆高熔点AlCrFeMoNb_xTiW高熵合金涂层组织及耐磨性能  

Microstructure and Wear Resistance of High-Melting-Point AlCrFeMoNb_xTiW High-Entropy Alloy Coating by Laser Cladding

作　　者：郭亚雄 刘其斌[1,2] 周芳[1] Guo Yaxiong;Liu Qibin;Zhou Fang(College of Materials and Metallurgy, Guizhou University, Guiyang 550025, China;Guizhou Province Key Laboratory of Materials Structure and Strength, Guiyang 550025, China)

机构地区：[1]贵州大学材料与冶金学院,贵州贵阳550025 [2]贵州省材料结构与强度重点实验室,贵州贵阳550025

出　　处：《稀有金属》2017年第12期1327-1332,共6页Chinese Journal of Rare Metals

基　　金：贵州省高层次创新型人才培养项目[黔科合人才(2015)4009号];贵州省工业攻关项目[黔科合GZ字(2015)3022号]资助

摘　　要：为了提高高速切削刀具的表面耐磨性能,设计了一种高熔点高熵合金成分体系,采用激光熔覆技术制备了AlCrFeMoNb_xTiW高熵合金涂层。利用光学显微镜(OM),X射线衍射(XRD),扫描电镜(SEM)等手段对其显微组织进行表征分析;利用显微硬度计、摩擦磨损试验机对涂层硬度及耐磨性能进行了检测。结果表明:熔覆层相组成主要由BCC,(Nb,Ti)C及Laves相所组成;当Nb原子分数为1时,涂层显微组织为胞状树枝晶及颗粒状碳化物;随着Nb原子比增加,涂层组织逐渐由放射状共晶向长条树枝状过共晶组织转变,但弥散分布的颗粒状(Nb,Ti)C始终存在于涂层内部。涂层硬度逐渐上升,当Nb原子分数为7时,涂层的最高硬度可达HV0.21017。磨损实验表明,各个Nbx涂层的平均摩擦系数差别不大;磨损量随着Nb含量的升高而降低;涂层磨损机制主要以磨粒磨损为主。To improve the wear resistance of high speed cutting steel, AlCrFeMoNbx TiW high-entropy alloy with high melting point coatings were prepared by laser cladding on the tool steel. Optical microscope （OM）, X-ray diffraction （XRD） and scanning electron microscope （SEM） （with energy dispersive spectrum （EDS）） were carried out to analyze microstructure of cladding layer, and micro- hardness and wear resistance were measured by micro hardness tester and the friction and wear tester. The experimental results indica- ted that the coating consisted of BCC phase, （ Nb, Ti） C and Laves phases ; while atom fraction of Nb content was 1, the microstructure of coating was cellular crystal and granular carbide （ Nb, Ti） C. As further increase of Nb content, the microstrueture transformed from radial eutectie to strip-like hypereutectic, moreover, the dispersiw~ distribution of （Nb, Ti）C always existed in the coating. With the content of Nb increasing, the microhardness of coating increased and the highest microhardness reached HV0.2 1017 in Nb7. The wear experiment showed that average friction coefficient was little different from each Nbx coating. The wear loss decreased while Nb content increased. The worn morphology showed that abrasive wear was the main wear mechanism.

关 键 词：激光熔覆 AlCrFeMoNbxTiw 高熔点高熵合金 高速切削刀具 耐磨性 

分 类 号：TG174.44[金属学及工艺—金属表面处理]