In-situ solid-state deformation-driven rapid reaction towards higher strength-ductility Al-CuO composites

Abstract

The strength-ductility dilemma of metallic matrix composites is mainly attributed to the mismatched phase/matrix interfaces, which induce stress concentration as dislocation piles up. Here, coherent nano-Al2O3 phases were in-situ formed in Al-CuO composites via rapid diffusion of neoteric deformation-driven metallurgy. The complex dislocation configuration was also promoted to induce the formation of about 14.5 % incoherent twin boundaries. The mean free path for dislocation movements was expanded, as dislocations could cut through the coherent nano-Al2O3 phases and interact with the incoherent twin boundaries without piled-up dislocations. The yield strength and elongation of the strength-ductility synergy Al-5CuO composites were 201 ± 14 MPa and 16.1 ± 0.5 %, indicating that in-situ Al2O3-Al coherent interface and incoherent twin boundaries exert remarkable ability of dislocation transmission.