Fe_xCoCrAlCu/Q235激光合金化层组织及性能研究

Study on Microstructure and Performance of a Fe_xCoCrAlCu/Q235 Laser Alloying Coatings

采用激光合金化法在Q235钢表面制备FexCoCrAlCu(x=0,0.5,1,2)高熵合金涂层。利用X射线衍射仪(XRD)、电子显微镜(SEM)、能谱仪(EDS)和显微硬度计对激光合金化层的相结构、显微组织、化学成分和硬度进行分析。结果表明,不同Fe含量的FexCoCrAlCu/Q235高熵合金化涂层均为具有简单体心立方(BCC)结构的固溶体,合金化层与基体间呈良好的冶金结合,显微组织为典型的枝晶组织,固溶体组织中出现了成分偏析现象。激光合金化层的显微硬度远高于基材Q235钢,且随着Fe主元含量的增加,涂层显微硬度呈下降趋势。FexCoCrAlCu/Q235激光高熵合金化层由表面至基材体系的混合熵呈高熵-中熵-低熵梯度变化。

Fe, CoCrAlCu （x = 0,0.5,1,2） high entropy alloy coatings are prepared by laser surface alloying on the surface of Q235 steel. The constituent phases, microstructure, chemical composition and microhardness of the laser alloying coatings are analyzed by X-ray diffraction （XRD）, scanning electron microscope （SEM）, energy disperse spectroscopy （EDS） and microhardness tester respectively. The experimental results show that Fe, CoCrAlCu/Q235 high entropy alloying coatings with different Fe content form single body-centered cubic （BCC） solid solution. The laser alloying coatings have good metallurgical bonding to the substrate. The solidfied microstructure is the typical dendritic structure with component segregation. The microhardness of the laser alloying coatings is much higher than that of the Q235 steel, and the microhardness of the coatings tends to decrease gradually with the increase of Fe content. From the surface of FexCoCrAlCu/Q235 laser high entropy alloying coatings to the substrate, the mixing entropy presents gradient distribution from high entropy, medium entropy to low entropy.