Formation mechanism and properties of FeCoCrNiAl x high-entropy alloy coatings by electrical explosion spraying

:FeCoCrNiAl x (x=0 ,0. 5 ,1. 0 ,mole ratio ,the same below ) coatings were prepared on the surface of TC4 titanium alloy by electric explosion spraying technology. The effects of Al content on the phase structure , surface morphology , microhardness and wear resistance of high -entropy alloy coatings were studied by means of XRD , SEM , EDS , microhardness tester and friction and wear test. The results show that the grain size of the coatings is nano -scale , and simple FCC , BCC and FCC+BCC solid solutions are formed. With the increase of Al element , the phase structure is gradually changed from FCC phase to BCC phase. The surface of the coatings is smooth and dense , without obvious cracks , and the elements are evenly distributed on the surface of the coatings , and no obvious segregation of elements is found. The scratch test shows that the average critical load for the failure of the FeCoCrNiAl 1. 0 coatings is 37. 2 N. The coating is metallurgically bonded to the substrate. The hardness and wear resistance of the coatings are positively correlated with the Al content. When x is 1. 0 , the average microhardness reaches the maximum value of 531. 8HV , which is about 1. 62 times that of the substrate. The FeCoCrNiAl 1. 0 coatings have the smallest amount of wear , and the wear resistance is about 3. 9 times that of the substrate. The wear mechanism is abrasive wear.