Microstructure and properties of Al2CrFeCoCuTiNix high-entropy alloys prepared by laser cladding

Abstract

The Al2CrFeCoCuTiNix high-entropy alloys were prepared by laser cladding. Using metallurgical microscope, scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation and tribometer the structure and hardness, corrosion resistance and wear resistance of Al2CrFeCoCuTiNix high-entropy alloys were tested. The result shows that, Al2CrFeCoCuTiNix high-entropy alloy samples consist of the cladding zone, bounding zone and heat affected zone. The bounding zone is between cladding layer and the substrate of a good combination; the cladding zone is composed mainly of axis crystal, nanocrystalline and fine white crystals. The Al2CrFeCoCuTiNix high-entropy alloys coating phase structure samples (FCC and BCC structure) due to high-entropy effect. The surface microhardness of Al2CrFeCoCuTiNix high-entropy alloys samples up to 1102 HV, about 4 times as the substrate, and the hardness increases with increasing Ni content. Al2CrFeCoCuTiNix high-entropy alloys coating has good corrosion resistance in 1mol/L NaOH solution and 3.5% NaCl solution. With the increase of Ni content, the corrosion resistance first increases and then decreases. The relative wear resistance of Al2CrFeCoCuTiNix high-entropy alloys coating shows a first increased and then a decreased trend with the increase of Ni content. Both the hardness and ductility are affected by wear resistance. The coating can play a good protective role on substrate Q235 steel.