Enhancing mechanical properties and improving mechanical anisotropy of rolled 2024 Al sheet by TiB2 nanoparticles

Abstract

Aluminum alloys with high mechanical properties and alleviated mechanical anisotropy are required for engineering applications. Traditional aluminum alloy sheets processed by rolling usually have a higher strength but a lower ductility, leading to a strength-ductility trade-off. Moreover, the rolling deformation could lead to obvious mechanical anisotropy. In this study, we report that the introduction of in-situ TiB2 nanoparticles can enhance the strength and ductility simultaneously of aluminum alloy in terms of rolled 2024 Al, which thus can overcome the strength-ductility trade-off dilemma faced by traditional aluminum alloy sheets. Moreover, the mechanical anisotropy of rolled 2024 Al can be alleviated significantly. The influencing mechanisms of TiB2 nanoparticles on strength-ductility and mechanical anisotropy are discussed in detail. The TiB2 particles enhance the strength of 2024 alloy mainly through grain boundary strengthening, Orowan strengthening, and load-bearing strengthening, and meanwhile enhance ductility through decreasing the dynamic recovery rate of dislocation. The mechanical anisotropy is alleviated by the elongated-to-equiaxed transition on grain structure and the weak texture. This study provides a new insight into the design of high-performance structural materials with alleviated mechanical anisotropy.