Investigation of the mechanical properties of TiC particle-reinforced Al–Cu alloys: Insights into interface precipitation mechanisms and strengthening effects

The increase in the mechanical performance of Al–Cu alloys through TiC particle reinforcement represents a significant improvement in the field of aluminum alloy strengthening. However, the precipitation behavior at the aluminum matrix and TiC interface requires further exploration. In this study, the induced precipitation mechanisms at the TiC interface and the impact of interface precipitates on bonding were investigated through scanning transmission electron microscopy (STEM) and first-principles calculations. The results indicate that θ′-Al2Cu exhibits heterogeneous nucleation on the TiC substrate, and the (100) Al/(110) θ′-Al2Cu/(100) TiC interface structure possesses the lowest formation energy. Consequently, the precipitation of θ′-Al2Cu at the Al/TiC interface demonstrates thermodynamic preference and energy stability. Tensile simulations reveal that the presence of interface precipitates effectively enhances the strength of the interface structure. Electronic structure analysis indicates a “barrel effect” in the stretched interface model, with fracture occurring in the weakest-bonded Al lattice near the phase interface. Additionally, θ′-Al2Cu, acting as an interface adhesive, enhances the chemical bond strength between Al and TiC interface atoms. This work provides novel insights into particle-induced interface precipitation behavior and interface fracture mechanisms.