Microstructure and mechanical properties of in situ TiC and Nd₂O₃ particles reinforced Ti-4.5wt.%Si alloy composites

(TiC+Nd₂O₃)/Ti-4.5wt.%Si composites were in situ synthesized by a non-consumable arc-melting technology. The phases in the composites were identified by X-ray diffraction. Microstructures of the composites were observed by optical microscope and scanning electron microscope. The composite contains four phases: TiC, Nd₂O₃, Ti₅Si₃ and Ti. The TiC and Nd₂O₃ particles with dendritic and near-equiaxed shapes are well distributed in Ti-4.5wt.%Si alloy matrix, and the fine Nd₂O₃ particles exist in the network Ti+Ti₅Si₃ eutectic cells and Ti matrix of the composites. The hardness and compressive strength of the composites are markedly higher than that of Ti-4.5wt.%Si alloy. When the TiC content is fixed as 10wt.% in the composites, the hardness is enhanced as the Nd₂O₃ content increases from 8wt.% to 13wt.%, but the compressive strength peaks at the Nd₂O₃ content of 8wt.%.