Research progress on microstructure tuning of heat-resistant cast aluminum alloys

With development of present energy-saving society, lightweight and green development in the automotive and aerospace industries have put forward urgent demands for heat-resistant cast aluminum alloys. Present cast aluminum alloys are of lightweight and have excellent mechanical properties when serving in ambient environment. However, when serving at temperatures of 200–300 ℃ or even higher, the alloys inevitably soften and the high-temperature mechanical properties decline rapidly, hardly meeting the requirements for high-performance equipments. This paper summarizes the development process of classic heat-resistant aluminum alloys, especially the microstructural characteristics of heat-resistant cast aluminum alloys in the past decade, and reviews the current microstructure tuning strategies of heat-resistant aluminum alloys from the aspects of intrinsic heat resistance of the second phases, phase interface modification, diffusion-controlled phase transition, grain boundary stabilization and composite material design. Finally, we propose the prospects for the future development of heat-resistant aluminum alloys.