Mechanical behavior of ultrahigh strength aluminum alloys

High-strength Al alloys, often referred to as Al alloys with mechanical strengths reaching 300–400 MPa, have widespread industrial applications. Recent applications call for Al alloys with much enhanced mechanical strength (> 600 MPa), good ductility, and high temperature thermal stability. However classical strengthening mechanisms for Al alloys, including precipitation-hardening (e.g., age-hardening), grain refinement, and solid-solution strengthening often lead to only moderate strength improvement. New mechanisms that can significantly improve the strength and thermal stability of Al alloys are urgently needed. In this review, we summarize strategies and mechanisms that may lead to ultrahigh-strength Al alloys defined as Al alloys with yield strength > 600 MPa . The mechanisms that improve ductility of ultrahigh-strength Al alloys are also discussed. This review article also points out challenges and future research directions for the discovery of ultrahigh-strength Al alloys with good ductility and high temperature thermal stability.