DISCONTINUOUSLY REINFORCED TITANIUM MATRIX COMPOSITES via COMBUSTION ASSISTED SYNTHESIS

摘要

Despite extensive research and development over the past two decades, titanium matrix composites have not realized their full commercial potential. For these composites the high value added costs of the available fabrication methods is largely due to the adverse liquid metal/reinforcement reactions. However, the combustion assisted synthesis technique, which involves the usual melting and casting of titanium in association with combustion synthesis reactions, has considerable potential for producing low cost composites with the required amounts of stable second phase reinforcements. This contribution discusses the novelty of this in situ technique to obtain an uniform distribution of TiB and Ti_2C reinforcements in Ti and Ti-6Al-4V matrices. Investigations reveal that reinforced Ti has 27% higher modulus, and reinforced Ti-6-4 has 22% higher modulus, compared to unreinforced matrices. It has been found that there is substantial increase in yield and tensile strength of Ti composite compared to unreinforced matrix, whereas the increase in strength of Ti-6-4 composite is relatively small. The ductility of composite is 1% at room temperature and increase with increase of temperature.