Titanium-based composites produced by powder metallurgy

Titanium-based metal-matrix composites, reinforced with ceramic particulates, have considerable potential for improvements in properties and service temperature, while retaining isotropic behaviour and ease of fabrication using conventional processing methods. However, the potential of titanium based composites can be limited by the extreme chemical reactivity of titanium with most ceramic materials which can result in the formation of a chemical reaction product at the matrix/ceramic interface. In this work, Ti-6%Al-4%V/TiC particle reinforced composites were fabricated using elevated temperature sintering and/or deformation processing. During processing, a reaction occurs between the Ti-6%Al-4%V matrix and TiC reinforcement to generate Ti2C at the interface. Fabrication of the composites by sintering alone indicated that high temperatures (>1500 degrees C) and long times (>4 hours) were necessary to achieve near complete densification. However, at temperatures above 1300 degrees C the rapid interfacial reaction results in extensive carbon loss from the TiC reinforcement particles. Through deformation-assisted sintering, the temperature and time for near complete consolidation were substantially reduced (i.e. 1000 degrees C and 1/2 hour), thereby minimizing the extent of reaction between the reinforcement and matrix.