AlCuFeMnNi高熵合金组织结构与耐磨性能研究

    Research on Microstructure and Wear Resistance of AlCuFeMnNi High-entropy Alloy

    • 摘要: 为了研究AlCuFeMnNi高熵合金的物相结构、显微组织、硬度和耐磨性能,采用X射线衍射仪、光学显微镜、显微硬度计和摩擦磨损试验机对真空熔炼制备出的AlCuFeMnNi合金进行测试。结果表明: AlCuFeMnNi合金是由BCC主相和FCC相构成的双相结构。AlCuFeMnNi合金显微组织是由BCC主相枝晶区域和FCC相晶间区域构成,属于典型的树枝晶结构。合金锭底部枝晶组织细小则是因为该区域界面热阻小、散热快、温差与过冷度大和形核速率高所致;顶部没有出现连片的晶间区域则是因为在凝固过程中被粗大枝晶“树杈”割裂成“小熔池”所致。AlCuFeMnNi高熵合金的显微硬度、摩擦因数和质量损失率分别为423.5 HV0.5、0.61和0.40%,其摩擦磨损曲线随时间的增长呈现先快速上升后稳定的趋势。这主要是因为摩擦初期摩擦因数随阻力和接触面积的增加而迅速增大和磨损机制由初期剥层磨损向后期氧化磨损转变所致。

       

      Abstract: In order to study the phase structure, microstructure, microhardness and wear resistance, AlCuFeMnNi high-entropy alloy prepared by vacuum melting was investigated by X-ray diffractometer, optical microscope, microhardness tester and friction-wear tester. The results show that AlCuFeMnNi alloy is a dual-phase structure composed of BCC main phase and FCC phase. The microstructure of AlCuFeMnNi alloy is composed of BCC dendrite region and FCC interdendrite region, which belongs to typical dendritic structure. The small dendrite structure in the bottom area of the ingot is due to the small interface thermal resistance, fast heat dissipation, large temperature difference and undercooling degree and high nucleation rate. There is no large region of interdendrite region in the top area, which is due to the "small molten pools" separated by the "branches" of coarse dendrites during the solidification. The microhardness, friction coefficient and mass loss rate of AlCuFeMnNi high-entropy alloy are 423.5 HV0.5, 0.61 and 0.40%, respectively. The friction-wear curve of AlCuFeMnNi alloy shows a rapid rise first and then a stable trend with the increase of time, which is mainly due to the rapid increase of friction coefficient with the increase of resistance and contact area at the initial stage of friction and the change of wear mechanism from the initial delamination wear to the later oxidation wear.

       

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