Multi-phase Al-based ultrafine composite with multi-scale microstructure

A new class of Al-base multi-phase ultrafine composites with multi-scale microstructure, which exhibits high strength and large compressive plasticity at ambient temperature, has been developed in the Al-Cu-Si ternary system. The formation of the favorable multi-phase multi-modal structure can be achieved by proper alloy selection and by controlling the solidification process. The developed hierarchical ultrafine composites exhibit high fracture strength of ∼1 GPa and large compressive plasticity up to ∼25%. The large macroscopic plastic strain is attributed to the combination of dislocation-based slip deformation in the ductile phase and extensive shear banding in the intermetallic phase.