The structure and properties of 2024 aluminum composites reinforced with TiO2 nanoparticles

The ultrafine-grained 2024 aluminum alloy (A2024) and A2024 matrix composites containing titanium oxide (TiO2, ~50 nm in size) are fabricated by conventional mechanical milling and hot-press process. With the aid of the optimum fabrication process, the TiO2 particles are well dispersed in the A2024 matrix. Owing to the characteristics of the TiO2 particles, the interface structure is found to be clean and clear without any micropores and contaminations. Without the strengthening by precipitates, the hardness, elastic modulus and yield stress are effectively increased with the increasing volume content of TiO2 particles up to 10 vol%. The strengthening effects by introducing TiO2 particles are evaluated by the thermally induced dislocation effect and the Orowan strengthening effect. The composite in the present study has great potential for application as structural materials.