Preparation and Mechanical Properties of Particulate-Reinforced Powder Metallurgy Titanium Matrix Composites

摘要

This research focuses on the in-situ synthesis of titanium (Ti)-titanium carbide (TiC) composites by powder metallurgy (PM) technology. Newly designed Ti-l.5Fe-2.25Mo-l.2Nd-0.3Al (wt pct) alloy was chosen as the matrix, and the additive was Cr_3C_2. The microstructure, room/elevated temperature, tensile behavior, and sliding wear behavior of the matrix alloy and the composites are presented and discussed. Microstructural analysis of the composites reveals a uniform dispersion of the TiC reinforcements with near-equiaxed shape in the Ti matrix. Tensile property test results show that the tensile strength increases significantly at both room temperature (RT) and elevated temperature after adding Cr_3C_2 into matrix alloy. Results of sliding wear resistance examination indicate that the wear properties are improved through the synthesis of TiC reinforcements. High strength of the composites, with Cr_3C_2 added, is attributed to particle strengthening, grain refining, and solution strengthening of Cr element. Better wear resistance of the composites is attributed to strong interface between particles and Ti matrix and high hardness of the composites. Therefore, Cr_3C_2 is considered to be a promising additive for processing PM Ti matrix composites.