Laser cladding of nano-TiC to enhance the wear and corrosion properties of AlcoCrFeNi high entropy alloy

Abstract:

Nano-TiC reinforced AlcoCrFeNi high entropy alloy coating was prepared on 304 stainless steel surface by laser cladding technique. The microstructure, phase structure and element distribution of the coating were systematically studied by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The hardness distribution, wear characteristics and corrosion resistance of the coatings were characterized by microhardness tester, friction and wear tester, ultra-depth of field microscope and electrochemical workstation. The results show that the quasi-spherical nano-TiC and rod-like micron TiC precipitates are uniformly distributed in the coated BCC (B2) matrix. The hardness of Alcocrfeni high entropy alloy coating increased by 15% after the addition of TiC phase compared with that without the addition of TiC. The surface wear rate and surface roughness per unit area (SA) decreased by 42% and 18%, respectively, compared with that of AlcoCrFeNi high entropy alloy coating. The dispersion strengthening effect of TiC reinforcing phase in the coating was the main reason for the improvement of coating hardness and wear resistance. The self-corrosion current of Alcocrfeni high entropy alloy coating with TiC is about one order of magnitude lower than that without TiC coating. The dense passivation film formed on the surface of the coating by TiC reinforcing phase is the main reason for its good corrosion resistance.

Key words:AlCoCrFeNi High entropy alloy;microstructure; Wear resistance; corrosion resistance