In-Situ Fabrication And Refinement Of Al-Matrix Composites Reinforced Jointly By Tib2 And Mg(2)Si Particles

To solve the problem that the volume fraction of in-situ TiB2 particle in Al-matrix composite is low, the in-situ (TiB2+Mg2Si)/Al composites with higher particle volume fraction were fabricated successfully. The microstructure of the composites was observed by SEM and the results revealed that TiB2 and Mg2Si particles are relative uniformly distributed in the matrix. X-ray diffraction was introduced to confirm the formation of TiB2 and Mg2Si phases, and no other intermediate phases like Al3Ti were found in the composites. The in-situ TiB2 particles are sub-micron in size, and Mg2Si phase is refined from Chinese script morphology to short dispersed sticks by TiB2 particles. The refined Mg2Si particles are under 10 mu m in size and about 10% in volume fraction. Therefore the whole volume fraction of particles is about 14%similar to 15%. The matrix grains are effectively refined. The mechanism of refinement is considered that the TiB2 particles and Mg2Si phases are mutually refined. The mechanical properties of the in-situ aluminum matrix composites have also been measured.