Study On The TiB₂-Al₂O₃-TiC Composite Powder Fabricated By SHS Reinforced Aluminum Matrix Composite

Aluminum matrix composites could be reinforced by TiB₂,TiC powders.In this paper,TiB₂-Al₂O₃-TiC composite powders were fabricated by SHS with industrial class TiO₂,Al and B₄C powders.Then five different TiB₂-Al₂O₃-TiC composite powder reinforced aluminum matrix composites were prepared by stirring casting.The contents of each composite powder in aluminum matrix composites were 0,3%,5%,10%,15wt.%,respectively.Constitution phase,grain size,grain appearance were investigated by X-ray diffraction and scanning electron microscope and the influence of excessive Al powder on materials microstructure and grain size was discussed.Constitution phase,microstructure, fracture appearance and mechanical properties were investigated by XRD, metallographic analysis,SEM,hardness test and tension test.The results of combustion synthesis indicated that the reactants of Al-TiO₂-B₄C system can mainly produce Al₂O₃,TiB₂ and TiC.The shape of Al₂O₃ was cubic or hexagon-bounded,and Al₂O₃ was surrounded by rodlike TiB₂. The result of comparative analysis showed that the average grain size of TiB₂-Al₂O₃-TiC composite powder increased with the content of Al increasing. TiB₂-Al₂O₃-TiC composite powder can refine the grain of aluminum matrix composites,especially the contents of composite powder were 15wt.%.The mechanical properties of aluminum matrix composites were significantly higher than pure aluminum,especially the contents of composite powder were 15wt.%.