Low-density NiAlFeCrMoV eutectic high-entropy alloys with excellent mechanical and wear properties

Abstract

Eutectic high-entropy alloys (EHEAs) have become a new research frontier and hot topic in the metallic materials community in recent years because of their excellent mechanical properties and great potential in practical engineering applications. In this work, a series of novel low-density (NiAl)100-x(FeCrMoV)x (x = 35, 40 and 45) EHEAs were designed and successfully prepared with arc-melting method. Their phase constitution, microstructure, mechanical and wear properties, as well as the deformation mechanisms were systematically investigated. It was shown that all the EHEAs are composed of BCC and B2 phases and their densities are less than 7 g/cm3. Typical hypoeutectic, eutectic and hypereutectic microstructures could be achieved as x = 35, 40 and 45, respectively. Significantly, as x = 45 the EHEA with hypereutectic microstructure possesses the best mechanical and wear properties at room temperature, of which the true and ultimate compressive yield stresses reach 1695.4 MPa and 2500.2 MPa, and the fracture strain and wear rate can reach 28.5% and 7.267 × 10−6 mm3N−1m−1, respectively, better than most HEAs reported previously. The excellent mechanical and wear properties can mainly be attributed to the small lattice mismatch between the BCC and B2 phases and the high hardness of the alloy. This work is significant because it could provide guidance for the design of high-performance alloys for practical engineering applications.