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 1.5GPa, while good work hardening capability is maintained. This study provides a new perspective on the design of high-strength Al alloys for various applications. [GRAPHICS] IMPACT STATEMENTThe flow stress of Al-Co alloys with high-density growth twins exceeds 1.5GPa, while maintaining good work hardening capability. The twins are stabilized by Co impurities based on DFT calculations.