Rare earth elements in cast aluminum alloys: Microstructural control and performance enhancement

Abstract

Aluminum alloys have been widely used in aerospace, automotive and electronics industries due to their light weight and high strength. However, traditional aluminum alloys often have problems such as coarse grains and uneven phases, which limit the overall performance of aluminum alloys. The addition of rare earth elements (REs) to aluminum alloys has been proven to be highly effective in improving their microstructure, mechanical properties, wear resistance and corrosion behavior. This paper mainly focuses on cast aluminum alloys and reviews the effects of rare earths on grain refinement, precipitation strengthening and stable formation of intermetallic compounds in aluminum alloys, and describes the mechanism of action of rare earth elements. These elements can reduce grain size by up to 50%, enhance tensile strength, and improve high-temperature stability. They also significantly enhance wear resistance by reducing the coefficient of friction and inhibiting the abrasive/adhesive wear mechanism. Meanwhile, the refinement of grains and the formation of new phases both affect corrosion resistance by influencing the corrosion potential. Despite these benefits, excessive rare earths may lead to brittle or unfavorable phase formation, so precise dose control is required. The future research directions are prospected, including exploring the synergistic effects of various rare earths, integrating advanced processing technologies, and optimizing the extreme environments of rare earth modified alloys. Overall, this work provides critical insights into the mechanisms and applications of REs in aluminum alloys, guiding the development of high-performance materials for industrial applications.