【摘要】 采用等离子熔覆技术在Q235钢基体上制备CoCrFeMnNi高熵合金涂层,通过正交试验法优化等离子熔覆工艺参数。利用XRD、SEM、EDS、EBSD以及显微硬度计对优化后熔覆层的组织和性能进行分析。结果表明,工艺参数对熔覆层稀释率的影响程度由大到小依次为行走速度、弧电流和送粉气流量,对熔覆层显微硬度的影响程度依次为弧电流、行走速度和送粉气流量。综合极差、方差和熔覆层宏观形貌分析,选出最优工艺参数组合为:弧电流70 A,行走速度7 mm/s,送粉气流量8 L/s。在此工艺参数下,熔覆层表面无明显的宏观裂纹,但存在一些孔隙、微孔以及少量的偏聚物。熔覆层物相以类Ni的FCC相为主,各主元素在熔覆层表面分布均匀。熔覆层晶粒尺寸以小于10μm为主,占92.7%。小角度晶界取向差在5°以内呈集中分布,而大角度晶界取向差在15～55°之间呈随机分布。熔覆层的稀释率约为17.86%,熔覆层表面显微硬度分布较均匀,而截面显微硬度受组织结构的影响呈梯度变化。更多还原

【Abstract】 The parameters of plasma arc welding(PAW) were optimized by orthogonal tests, the CoCrFeMnNi high entropy alloy coating was prepared by PAW on Q235 steel substrate. The microstructure and properties of cladding layer were analyzed by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), electron back scatter diffraction(EBSD) and microhardness tes-ter.The results showed that the significance influence of plasma process parameters on the dilution ratio of cladding layer is in turn with welding speed, the arc current and feeding gas flow, but which on the microhardness of cladding layer is in turn with the arc current, welding speed and feeding gas flow. The optimal parameter combination obtained by the range, variance and macromorphology of cladding layer is welding current of 70 A, welding speed of 7 mm/s, feeding gas of 8 L/s. Under these conditions, the cladding layer has no obvious macroscopic crack, but it has many pores, micro holes and few aggregations. The cladding layer is mainly composed of FCC structure phase as the type phase of Ni, the main elements are uniformly distributed on the cladding layer surface. The diameter of 92.7% grains within cladding layer surface is less than 10 microns. The oriention distribution of the low-angle grain boundarys(LAGBS) is concentrated within 5°, but that of the high-large angle grain boun-darys(HAGBS) is randomly distributed at 15—55°. The dilution ratio of the coating layer is about 17.86%. The hardness distribution on cladding layer surface is relatively uniform, however, that of the cross-section is changed with the gradient for microstucture.更多还原