Uncovering wear mechanism of a Fe2Ni2CrAl multi-principal elements alloy

Abstract

Fe2Ni2CrAl multi-principal elements alloy (MPEA) has been regarded as promising candidate for engineering application due to its desirable combination of strength and plasticity. In this work, the microstructure, hardness and wear resistance of Fe2Ni2CrAl MPEA were systematically investigated. This alloy has a dual-phase structure, comprised of the FCC and BCC/+B2 phase. The average nanohardness is 4.59 GPa, and the average elastic modulus is 199.4 GPa. By performing reciprocating ball-on-flat friction tests, the Fe2Ni2CrAl MPEA shows good wear resistance, with a wear rate of 8.72 × 10−5 mm3/(Nm) and average friction coefficient of ~ 0.54. The wear mechanisms are a mixture of adhesive, abrasive and oxidation wear, accompanied by cracks and delamination. Molecular dynamics (MD) was utilized to study the wear behavior at nanoscale. The surface suffers severer deformation during the first slide. Then, the reciprocating friction contributes to the surface strain hardening in the later slide. The large displacement and shear strain region were concentrated below the rigid ball, and the atomic damage was identified. Fewer dislocations are produced during reciprocating friction, accompanied with the reduced atomic shear strain and lattice deterioration. The Shockley-type dislocation plays a dominant role in the whole nano-wear process. This work explored the friction behavior in depth and provided a deep insight into wear mechanisms for Fe2Ni2CrAl MPEAs.