Metastable FeCrMnCo HEAs with the reinforcement of tungsten carbide fabricated by laser melting: Microstructure, mechanical properties and tribological behaviors

Abstract

Fe50Mn30Co10Cr10 high entropy alloy (HEA) can be considered as a candidate structural and functional material, but the early failure during friction with heavy load can limit its more extensive applications. In this paper, a series of tungsten carbide particle reinforced Fe50Mn30Co10Cr10 HEAs were fabricated by laser cladding technique, the influence of tungsten carbide content on microstructure, mechanical properties and tribological behaviors were explored systematically. The results indicated that the dissolution and diffusion of tungsten carbide could contribute to a wettability between tungsten carbide and HEA matrix, and grain refinement was caused by increasing tungsten carbide. The UTS and EL of the P10 sample are increased by simultaneously by 26.8% and 31.1% compared with UTS of 696 MPa and EL of 15.1% for P5 sample. UTS and EL were enhanced simultaneously owing to fine-grained strengthening and nanoscale precipitate strengthening. But higher content of tungsten carbide could cause lower elongation owing to the embrittlement of the materials. Just as this, Rockwell hardness and friction coefficient has an increasing trend with increasing tungsten carbide when an opposite trend exists in volume wear rate. It can indicate that hardness is a more important factor for wear resistance, and excellent wear resistance with 1.25 × 10−5 mm3/(N·m) appear in higher-content WCp reinforced HEA composite. Furthermore, wear mechanism is transformed from abrasive wear in low-content tungsten carbide to adhesive wear in high-content tungsten carbide.