Microstructural and performance characterization of in-situ biphasic micro-nano scale (TiB2-TiCx)/Al-Cu-Mg composites with different ceramic and metal ratios designed for compact integration

Abstract

Based on the principle of bionics, the lightweight and high-strength the Neptune’s shell was chosen as a bionic model for this study due to its light weight and high strength. Micro-nano mixed-scale dual-phase reinforced aluminum matrix composites were prepared by one-step densification of combustion synthesis combined with hot pressing. We aimed to control the particle size of the ceramic and the ratio of the soft and hard phases by controlling the composition of the composite, and to study the mechanical properties of the biomimetic structure of the composite at normal and high temperatures. The results showed that as the aluminum content in the composite decreased, the ceramic particle size increased and the ceramic particles became evenly distributed in the matrix. Compression testing showed that as the ceramic volume fraction increased the ultimate compressive strength (σUCS) and fracture strain (εf) first increased and then decreased, both at room temperature and at 473 K and 523 K. (TiB2-TiCx)/Al-Cu-Mg composites of 40 vol.% exhibited optimal compressive properties at room temperature and at high temperatures. The increase in the size of the ceramic particles caused an increase in the spacing between the particles, which also weakened the bonding strength between the ceramic particles and the aluminum matrix. Therefore, when the ceramic volume fraction exceeded 40% by volume, the compression properties of the composite tended to decrease. The coupling effect of the layered structure and the soft-hardened structure played a key role in the stability of the biomimetic composite.