Optimization of the microstructure, mechanical properties, and wear resistance of nacre-inspired TiB₂/Al-Cu composites via gelatin addition

Nacre-inspired TiB₂/Al-Cu composites were prepared by freeze casting and squeeze casting. This study focused on the effect of gelatin content on microstructure, mechanical characteristics, and wear resistance of the composites. The structure formation, as well as the fracture and wear mechanisms of the composites, was analyzed. The results demonstrate that both the compressive and bending strength and the toughness of the TiB₂/Al-Cu composites improved with gelatin addition. The composites with 1.0 wt% gelatin content achieved optimal mechanical properties, with a compressive strength, bending strength, crack-initiation toughness (K_IC), and crack-growth toughness (K_JC) of (625±13) MPa, (626±4) MPa, (22.23±0.2) MPa ∙ m^1/2, and (54.43±2.4) MPa ∙ m^1/2, respectively. Moreover, the gelatin addition improved the wear properties of the laminated TiB_2/Al-Cu composites significantly. The bent ceramic layer and increased ceramic bridging are responsible for the improved strength, toughness, and wear resistance of the TiB₂/Al-Cu composites inspired by nacre with gelatin addition, which further increased the potential of multiple cracks and reduced the Al layer’s ability to deform plastically.