High strength, deformable nanotwinned Al–Co alloys

Aluminum (Al) alloys have been widely used in the transportation industry. However, most high-strength Al alloys to date have limited mechanical strength, on the order of a few hundred MPa, which is much lower than the flow stress of high-strength steels. In this study, we show the fabrication of nanocrystalline Al alloys with high-density growth twins enabled by a few atomic percent of Co solute. In situ uniaxial compression tests show that the flow stress of Al–Co solid solution alloys exceeds 1.5 GPa, while good work hardening capability is maintained. This study provides a new perspective on the design of high-strength Al alloys for various applications. IMPACT STATEMENT: The flow stress of Al–Co alloys with high-density growth twins exceeds 1.5 GPa, while maintaining good work hardening capability. The twins are stabilized by Co impurities based on DFT calculations.