Room‐Temperature Superformability in Novel As‐Cast High‐Entropy Alloy During Compressive Loading

Abstract

Conventional alloys show low compressive strength and strain accommodation due to their propensity for limited strengthening mechanisms and rapid compressive instability. High‐entropy alloys (HEA) may overcome this limitation by metastability engineering. Inspired by this, herein, a dual‐phase Fe44Mn20Cr15Ni7.5Co6Si7.5 HEA (M‐HEA) which shows maximum engineering strength of ≈4.4 GPa at true compressive strain of ≈2.2 (engineering strain of 90%) in as‐cast condition due to controlled hardening and sustained softening response during deformation is presented. The controlled hardening phenomenon (up to 60% strain) is attributed to transformation‐induced plasticity in γ‐phase and nanotwinning in untransformed γ‐phase. The sustained softening is a result of extensive strain accommodation by both γ‐ and β‐phases via dynamic recovery in γ‐phase and shearing of β‐phase during deformation. Hence, this superformability in M‐HEA makes it an excellent material for structural applications in comparison with other conventional alloys and HEAs.