Laser surface alloying of FeCoCrAlNiTi high entropy alloy composite coatings reinforced with TiC on 304 stainless steel to enhance wear behavior

Abstract

FeCoCrAlNiTi + x%TiC (x = 10 and 30) high entropy alloy (HEA) composite coatings were deposited by laser surface alloying (LSA), aiming at studying the influence of TiC addition on wear resistance. The formed phases, microstructural evolution, hardness and wear behavior of the HEA composite coatings before and after 10-h anneal at 700 °C were clarified in detail by using XRD, SEM, EDS, Vickers hardness measurement and linearly reciprocating friction-wear measurement. The results displayed that three-phase FCC + BCC + TiC was appeared for HEA composite coatings with x = 10 and 30. The formed phases for the HEA coatings with x = 10 and 30 remained unchanged after 10-h annealing at 700 °C. The coatings exhibited dense microstructures, in addition to a good metallurgical bonding to the substrate. TiC particles displayed relatively homogeneous distribution in the matrix for HEA composite coatings with x = 10 and 30. The grains of the HEA matrix were obviously refined due to the TiC particles addition. The nano-hardness (H), nano-hardness/elastic modulus (H/E) and (H3/E2) of HEA composite coatings was obviously increased with the addition of TiC and the HEA composite coatings with x = 30 showed the highest nano-hardness, the ratio of H/E and H3/E2, possessing high resistance to plastic deformation. With the increase in nano-hardness, the specific wear rate of the HEA composite coatings with x = 30 was the lowest with the value of 2.636 × 10−5 mm3/N m, indicating that it possessed the highest wear resistance. In addition, the HEA composite coatings in the current study also displayed an enhanced wear performance compared to the monotonous FeCoCrAlNiTi HEA coating reported in previous work.