A Review of Heat-Resistant Al Alloys: Strengthening Strategies and Processing Technologies

ABSTRACT: The rapid advancement of aerospace and transportation technologies toward weight reduction and harsh thermal environments has imposed a stringent demand for Al alloys that can sustain excellent performance at 200–400 °C. Heat-resistant Al alloys have thus garnered strategic significance as a premier class of lightweight structural materials for elevated-temperature applications. This review critically assesses the current state of heat-resistant Al alloys from the perspectives of strengthening strategies and processing technologies. Three representative strengthening strategies have been summarized, including multi-element microalloying, incorporation of nanoparticles, and formation of nano-eutectic skeleton. Meanwhile, a systematic comparative analysis has been conducted on microstructural regulations and mechanical properties of alloys manufactured by permanent mold casting (PMC), powder metallurgy (PM), and laser powder bed fusion (LPBF), with particular emphasis on the processing-structure-property correlations unique to each route. On this basis, the principal technical bottlenecks currently constraining the further advancement of high-performance heat-resistant Al alloys have been identified and critically discussed, thereby outlining prospective research directions to overcome these limitations.