Friction–wear behaviors and microstructure of AlTiVCrNb lightweight refractory high-entropy alloy coating prepared by laser cladding on Ti–6Al–4V substrate

To enhance the friction and wear properties of Ti–6Al–4V, the AlTiVCrNb lightweight refractory high entropy alloy coating was applied to a Ti–6Al–4V substrate by laser cladding. The microstructure was investigated through scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The results demonstrate that the coatings are metallurgically bonded to the Ti–6Al–4V substrate, and the microstructure of the AlTiVCrNb coatings with high Ti content comprises disordered BCC phases, laves reinforced phases, and diffusely distributed Ti2AlNb nanophases. The microhardness of the coating measures 548.54 HV0.1, surpassing that of the Ti–6Al–4V substrate by 1.57 times. The wear resistance of the AlTiVCrNb HEA coating is 1.58 times higher than that of the Ti–6Al–4V alloy under a 20 N load, thereby effectively improving the wear resistance of the Ti6Al4V alloy. The main wear mechanisms of AlTiVCrNb high-entropy alloy coatings are oxidative and adhesive wear.