In-Situ Synthesis of Multiscale Al2O3 and AlSi3Ti2 Reinforced Al Matrix Composites Based on Al12Si-TiO2 System

In situ particle reinforced aluminum matrix composites have become an important development in the field of materials science due to their unique reinforced structure design and excellent mechanical properties. In this paper, in situ Al2O3 and AlSi3Ti2 particle reinforced Al12Si matrix composites were prepared via powder metallurgy. The microstructure and mechanical properties of the composites were analyzed systematically. With the increase in TiO2 content, the grain size of the composites was refined, resulting in the composites exhibiting higher strength. The in situ generated AlSi3Ti2 phase has a higher Young's modulus of elasticity compared to the Si phase. The in situ formed nano-Al2O3 and micrometer AlSi3Ti2 formed a strong interfacial bonding with the matrix, which ensured a good reinforcement effect. At the same time, the introduction of reinforced particles also changed the texture characteristics of extruded Al12Si, from <001>parallel to ED of Al12Si to <111>parallel to ED of composite. As a result, the strength of the Al12Si-7TiO2 composite was 330 MPa, which is a 120% enhancement compared with that of the matrix. The hardness reached 107 HV, an increase of 80% compared to the matrix. This study can provide a reference value for the design of new multi-particle hybrid reinforced composites to enhance the material properties.