Ultrastrong and ductile W–Cu composites via Al- mediated interfacial diffusion layers and matrix-nanoclusters networks

Abstract

W–Cu composites are integrated materials with both structural and functional properties. However, the weak interfacial bonding capability leads to limited strain hardening, which makes it difficult to take full advantage of the coordination of the biphasic materials. In present work, a multistage strain-hardening (MSH) effect is created, which enables the W–Cu composites to possess a persistent and effective strain-hardening capability. The prepared W-30(CuAl5) (wt.%) alloy has significant tensile ductility (∼21 %) and ultra-high yield strength (∼840 MPa). Remarkably, compared to the original W–30Cu without Al alloying, the strength and ductility are over two and three times, respectively, accompanied by the preservation of an electrical conductivity of about 80 %. This excellent synergistic effect stems from the Al-mediated interpenetrating interfacial diffusion layers and matrix-nanoclusters interconnection networks. As a result, a high-density of dislocation segments, self-locking structures, and a variety of twinning mechanisms such as nanotwins and 9R configurations are sequentially activated, allowing the composites to accommodate ductility deformation while simultaneously facilitating interactions that produce three unusual rises in strain-hardening rate. The present work offers a critical perspective on the realization of a synergistic ultrahigh tensile ductility and strength combination in metal matrix composites.