Fabrication and wear behavior of TiC reinforced FeCoCrAlCu-based high entropy alloy coatings by laser surface alloying

Abstract

High entropy alloy (HEA) coatings of FeCoCrAlCu reinforced by TiC were successfully fabricated on Q235 steel by laser surface alloying (LSA). The effect of various TiC content on the constituent phases, microstructure, chemical composition, and grain orientation of the HEA coatings were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron backscattered diffraction (EBSD), respectively. The microhardness and wear properties of the HEA coatings were investigated using micro-hardness tester and wear tester, respectively. Experimental result confirmed that with the optimized processing parameters, the FeCoCrAlCu-based HEA coatings free of pores and cracks were achieved, in addition to obtaining good metallurgical bonding between coating and substrate. The coatings were made up of a single BCC solid solution and a few TiC phases. EBSD maps of the HEA specimens exhibited anisotropy due to the complex heat flux direction during LSA process. The microhardness and the wear resistance of the FeCoCrAlCu-xTiC (x = 0, 10, 30, 50 wt%) composite coating were improved with the volume of TiC increasing from 0 wt% to 50 wt%. Especially for FeCoCrAlCu-50 wt%TiC composite coating, the microhardness, wear volume and specific wear rate were 10.78 GPa, 5.2 × 105 μm3 and 9.6 × 10−5 mm3/N m, respectively.