Mechanical Responses and Deformation Mechanisms of Low-Cost High-Entropy Alloy AlCrFe₂Ni₂ with Heterogeneous Structure Subjected to High-Strain Rate Deformation

Abstract

Introducing heterogeneous structures into metallic materials through composition design is a promising strategy for simultaneously improving the strength and ductility of the materials. In this work, a novel dual-phase low-cost AlCrFe2Ni2 high-entropy alloy (HEA) was designed and prepared. Its phase constitution, microstructure, dynamic mechanical responses at strain rates ranging from 1100[Formula: see text]s[Formula: see text] to 4800[Formula: see text]s[Formula: see text] as well as deformation mechanisms were investigated. It was found that the HEA consists of FCC, B2 and BCC phases and has a heterogeneous microstructure containing dual-phase alternate lamellar and high-density precipitates. The HEA displays the optimal mechanical properties at the strain rate of 4800[Formula: see text]s[Formula: see text], of which the yield strength, maximum flow stress and strain are 1222.9[Formula: see text]MPa, 2340.8[Formula: see text]MPa and 30.5[Formula: see text]%, respectively, better than that of most single-phase FCC or BCC HEAs, dual-phase HEAs and traditional alloys. The deformation mechanism of the HEA at the strain rate of 4800[Formula: see text]s[Formula: see text] involves both dislocation slip and deformation twinning, with the former dominating. This work could provide guidance and insights for designing metallic materials with excellent mechanical properties at high strain rates.