激光熔覆AlxCoCrFeNi2.1高熵合金涂层的微观组织与性能研究

    Microstructure and Properties of AlxCoCrFeNi2.1 High Entropy Alloy Coating by Laser Cladding

    • 摘要: 利用激光熔覆技术在304不锈钢表面制备了AlxCoCrFeNi2.1x=1.0,1.2,1.4)高熵合金涂层。通过X射线衍射仪(XRD)、扫描电镜(SEM)、显微硬度计和摩擦磨损试验机研究了高熵合金涂层的相结构、显微组织、显微硬度和耐磨性。结果表明,AlxCoCrFeNi2.1高熵合金涂层均由面心立方(FCC)相和体心立方(BCC)相组成。当x=1.0时,涂层的微观组织为柱状树枝晶;当x=1.2时,涂层的中心区域呈现出过共晶组织,而涂层的底部区域呈现出完全共晶组织;当x=1.4时,涂层的微观组织为胞状晶。涂层的显微硬度随着Al元素的增加而增大,最高达到444.1 HV0.2。随着Al元素的增加,AlxCoCrFeNi2.1高熵合金涂层的耐磨性不断提高,涂层的主要磨损机制由黏着磨损向磨粒磨损转变。

       

      Abstract: AlxCoCrFeNi2.1(x =1.0, 1.2, 1.4) high entropy alloy coatings were prepared on 304 stainless steel by laser cladding technology. The phase structure, microstructure, microhardness and wear resistance of the high-entropy alloy coatings were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), microhardness tester and friction/wear testing machine. The results show that AlxCoCrFeNi2.1high entropy alloy coatings are composed of face-centered cubic(FCC) phase and body-centered cubic(BCC) phase. When x=1.0, the microstructure of the coating is columnar dendrites;when x=1.2, the central region of the coatings exhibits hypereutectic structure, while the bottom region of the coatings exhibits complete eutectic structure; when x=1.4, the microstructure of the coating is cellular crystals. The microhardness of the coating increases with the increase of Al content, and the maximum is 444.1 HV0.2. With the increase of Al element, the wear resistance of AlxCoCrFeNi2.1high entropy alloy coatings improves, and the dominant wear mechanism of the coatings changes from adhesive wear to abrasive wear.

       

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