A review of the design of high-entropy aluminum alloys: a pathway for novel Al alloys

Abstract

Aluminum (Al) alloys are of great importance and interest because of their extensive applications in various engineering fields. Lightweighting of our infrastructure has been a driver for more than the last two decades as our need to reduce carbon footprint on a global scale has become an inevitable reality. As a result, we have witnessed much progress in alloy development in Al alloys, especially with the advent of Integrated Computational Materials Engineering (ICME) and other computational tools. However, the limitations of the properties one may attain through alloy development to date have relied on the traditional solvent/solute model, where the matrix is Al with additions of elements (solute) to the matrix. Despite making much progress, we are still lockedin to the strength-ductility curve without any appreciable increase in modulus (stiffness) of the alloy. High Entropy Alloys (HEAs) provide a new paradigm as they differ from conventional alloys in entropy-based mixing logic of various elements, which is different from the solvent/solute model. HEAs offer the opportunity to move out of the strength-ductility curve as well as the opportunity to increase the alloy's modulus. In this paper, we present a retrospective view of Al alloys, followed with an understanding of the principles of HEAs, and lastly, with the idea of applying high entropy concept to conventional Al alloys to develop a novel Al alloy category, which we have coined HEAl. Preliminary results with a commentary on potential future opportunities are also given.

High-Throughput CALPHAD: A Powerful Tool Towards Accelerated Metallurgy

“…The HT-CALPHAD technique has been used for developing various types of alloys, such as alloys with an austenitic matrix containing a secondary coherent phase that is stable at a wide range of temperatures (Tripathi et al, 2021), screening for alloys containing solid-solution (SS), intermetallic (IM), and SS + IM phases (Senkov et al, 2015a), HEAs with stable disordered single phases at low temperatures (Klaver et al, 2018), and to developing lightweight HEAs (Asadikiya et al, 2021).…”

Hot Deformation Behavior and Microstructure Evolution of a Novel Al-Zn-Mg-Li-Cu Alloy

“…Little attention has been paid to Al-Zn-Mg-Cu alloys with a high content of strengthening elements. The concept of entropy increasing in high-entropy alloys brings new inspiration to the design of aluminum alloys [ 12 , 13 , 14 , 15 , 16 ]. Researchers have sought to increase the contents of multiple alloying elements and at the same time strengthen and toughen the alloy.…”

X-ray Thermo-Diffraction Study of the Aluminum-Based Multicomponent Alloy Al58Zn28Si8Mg6

“…Over the past decade, research has been extended to other alloy classifications that have evolved from the original HEA concept: “medium-entropy alloys” (MEAs) [ 9 ], “non-equiatomic HEAs”, or “multi-phase HEAs” that may contain bulky secondary phases [ 10 ]. In fact, the idea of intentionally having secondary phases in this type of alloy was first suggested by Miracle et al [ 11 ].…”

“…Asadikiya et al considered that the application of the entropy concept in aluminum alloys may be the answer to the challenge of developing novel Al alloys with improved properties [ 10 ]. Therefore, multicomponent lightweight alloys continue to be researched for their potential applications.…”