添加Ti对AlCuFeMnNi高熵合金组织和耐磨性的影响

为研究添加Ti元素对AlCuFeMnNi高熵合金组织和耐磨性的影响，采用真空电弧熔炼技术制备了等摩尔比的AlCuFeMnNi和AlCuFeMnNiTi合金。利用X射线衍射仪、金相显微镜、扫描电镜、显微硬度计和摩擦磨损试验机测试了上述两种合金的物相组成、显微组织、硬度和摩擦磨损性能。结果表明，添加Ti元素后，AlCuFeMnNiTi合金由原来的FCC与BCC1双相结构转变为FCC、BCC1与BCC2三相结构，其点阵常数和晶胞体积均有所增大。两种合金均为典型的树枝状晶，Ti元素的添加使合金晶粒逐步细化，枝晶区域面积增加，晶间区域面积减小，枝晶区域弥散分布有少量领先相BCC2。添加Ti元素后，合金的硬度由423.5 HV0.5提高到498.0 HV0.5;质量损失率和摩擦因数则分别由0.43%、0.59降低至0.39%、0.46,摩擦因数呈先增大后稳定的变化趋势。AlCuFeMnNiTi合金硬度和耐磨性能的提高主要是由Ti元素的添加所引起的细晶强化、固溶强化和晶体结构向高强相转变的综合作用所致。

Effect of Ti addition on microstructure and wear resistance of AlCuFeMnNi high entropy alloy

In order to study the effect of Ti addition on microstructure and wear resistance of AlCuFeMnNi high entropy alloy, AlCuFeMnNi and AlCuFeMnNiTi alloys with equal molar ratio were prepared by vacuum arc melting technique. The phase composition, microstructure, hardness and tribological properties of the two alloys were tested by X-ray diffractometer, metallographic microscope, scanning electron microscope, microhardness tester and friction and wear tester. The results show that with the Ti addition, the phases of the AlCuFeMnNiTi alloy changes from FCC and BCC1 two-phase structure to FCC, BCC1 and BCC2 three-phase structure, and the lattice constant and cell volume of AlCuFeMnNiTi alloy increase. The microstructure of the both alloys are typical dendritic grains. The addition of Ti gradually refines the grains of the alloy, increases the area of the dendrite region, decreases the area of the intergranular region, and makes a small amount of leading phase BCC2 distributed dispersively in the dendrite region. After the addition of Ti, the hardness of the alloy increases from 423.5 HV0.5 to 498.0 HV0.5, the mass loss rate and friction coefficient decreases from 0.43% and 0.59 to 0.39% and 0.46, respectively, and the friction coefficient increases first and then stabilizes. The increase of hardness and wear resistance of the AlCuFeMnNiTi alloy is mainly due to the combined effects of fine grain strengthening, solution strengthening and crystal structure transformation to high strength phase caused by the Ti addition.