Microstructure and Wear Resistance of FeCuNiTiAl High-Entropy Alloy Coating on Ti6Al4V Substrate Fabricated by Laser Metal Deposition

In order to improve the hardness and wear resistance of titanium alloys, an equimolar ratio high-entropy alloy (HEA) FeCuNiTiAl coating was fabricated on the surface of titanium alloy Ti6Al4V by means of laser metal deposition for the first time. The microstructure and composition of the HEA coating and the transition zone were observed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results show that HEA coating and Ti6Al4V have suitable metallurgical bonding, and no defects, such as cracks, are found at the interface. The hardness of the HEA coating is between 450 and 500 HV0.5, which is about 1.5 times that of the Ti6Al4V substrate. Wear tests show that the wear rate of HEA coating is 0.89 × 10−5 mm3/(N·m), while that of Ti6Al4V reaches 53.97 × 10−5 mm3/(N·m), and the wear resistance of substrate is increased 60 times by the HEA coating. The wear mechanism of the Ti6Al4V substrate is mainly abrasive wear, and the wear mechanism of FeCuNiTiAl HEA coating is mainly adhesive wear, accompanied by slight oxidation wear and abrasive wear.