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

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. © 2023 Elsevier B.V.