Enhanced strength and ductility in ZrB2/2024Al nanocomposite with a quasi-network architecture

In order to achieve high strength and high ductility, 2 vol.% ZrB2/2024Al nanocomposite with a quasi-network reinforcement distribution was designed and prepared by a combination of direct melt reaction and T6 heat treatment. The microstructural evolution shows that the in situ ZrB2 nanoparticles were self-assembled into clusters that were pushed towards α-Al boundaries and formed a quasi-network architecture; T6 heat treatment effectively eliminated interference of the coexisting eutectics. As expected, the unique heterogeneous structure results in a remarkable increase in the tensile modulus, strength and ductility of as-fabricated composite as compared with the matrix alloy. The superior strengthening effect can be attributed to the novel quasi-network architecture, matrix grain refinement and excellent load-bearing capacity, while the ductility enhancement can be ascribed to the matrix grain refinement and high damage tolerance of ZrB2 nanoparticle clusters.