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

(TiC + Nd2O3)/Ti-4.5 wt.%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-4.5 wt.%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-4.5 wt.%Si alloy. When the TiC content is fixed as 10 wt.% in the composites, the hardness is enhanced as the Nd2O3 content increases from 8 wt.% to 13 wt.%, but the compressive strength peaks at the Nd2O3 content of 8 wt.%. (C) 2011 Elsevier Ltd. All rights reserved.