Creep Behavior of High-Entropy Alloys: A Critical Review

TL;DR

This review critically assesses the current understanding of high-temperature creep behavior in high-entropy alloys, highlighting mechanistic differences from conventional alloys and discussing challenges and future directions for designing creep-resistant HEAs.

Contribution

It provides a comprehensive analysis of creep mechanisms in HEAs and identifies key challenges and research directions for high-temperature applications.

Findings

HEAs show different creep mechanisms compared to conventional alloys.

Phase stability influences creep resistance at high temperatures.

Designing creep-resistant HEAs remains a significant challenge.

Abstract

High-entropy alloys (HEAs) comprise a compositionally complex class of materials that in certain cases exhibit outstanding mechanical properties. While substantial progress has been made in understanding their phase stability, microstructure, and deformation mechanisms at room and cryogenic temperatures, the long-term creep behavior (>100 h) of HEAs at high temperatures (>0.6 Tm, where Tm is the melting temperature) remains relatively underexplored. This knowledge gap is critical, as many engineering applications, including those in aerospace, power generation, aero engines and nuclear energy, require materials with good creep resistance to maintain structural integrity over extended service lifetimes. This review provides a focused and critical assessment of the current understanding of high-temperature deformation and creep behavior of HEAs, with particular attention paid to face-centered cubic HEAs and body-centered cubic refractory HEAs. The underlying deformation mechanisms governing their creep response and the influence of phase stability at elevated temperatures are examined in detail. Recent studies reveal mechanistic differences between HEAs and conventional dilute alloys that do not always lead to improved creep resistance belying their initial promise. Based on these findings, we discuss the challenges in designing HEAs for high-temperature structural applications and outline future research directions that may lead to creep-resistant HEAs.