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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AlCrFeMoNbxTiW高熵合金涂层。利用OM,XRD,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原子比为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原子比为7时,涂层的最高硬度可达1017HV0.2。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。
In order to improve the surface wear resistance of high-speed cutting tools, a high-melting-point high-entropy alloy composition system was designed and AlCrFeMoNbxTiW high-entropy alloy coating was prepared by laser cladding. The microstructure of the coating was characterized by OM, XRD and SEM. The hardness and wear resistance of the coating were measured by microhardness tester and friction and wear tester. The results show that the phase composition of the coating is mainly composed of BCC, (Nb, Ti) C and Laves phases. When the Nb atomic ratio is 1, the microstructure of the coating is cellular dendrites and granular carbides. With Nb As the atomic ratio increases, the microstructure of the coating gradually changes from radial eutectic to long dendrite hypereutectic structure, but the dispersed particles (Nb, Ti) C are always present in the coating. Coating hardness gradually increased, when the Nb atomic ratio of 7, the maximum hardness of the coating up to 1017HV0.2. The wear tests show that the average friction coefficient of each Nbx coating is not different. The wear amount decreases with the increase of Nb content. The wear mechanism of the coating is mainly abrasive wear.