Lightweight Al-based entropy alloys: Overview and future trend

The emergence of a new generation of alloys, namely high-entropy alloys, has revealed the significance of the entropy effect in alloy design. Inspired by this concept, lightweight Al-based entropy alloys have been proposed recently. With increasing demand for low-density structural materials, these new alloys have significant potential for diverse applications. This review provides an overview of lightweight Al-based entropy alloys, covering their developmental background, design principles, fabrication methods, microstructures, and mechanical properties, as well as alloys suitable for high-temperature applications. A comprehensive investigation of current research on Al-based entropy alloys with a density lower than 4.0 g cm−3 was conducted from 122 different alloys. Lightweight Al-based entropy alloys could bridge the gap between conventional Al and Ti alloys in terms of mechanical properties and density. The excellent thermal stabilities of these alloys make them attractive structural materials for use at elevated temperatures. In addition, machine learning has been suggested as an effective computational tool for alloy development. Finally, future trends in the field of lightweight Al-based entropy alloys are discussed.