Densification Behaviour and Properties of Ti-based Alloys Consolidated by Spark Plasma Sintering

Titanium alloys have been successfully utilised in many aerospace and military applications. However, the high cost of manufacturing has hindered use of titanium alloys. Considerable effort has been dedicated to simplifying the complex processing steps, and the powder metallurgy (PM) approach offers considerable potential. Spark plasma sintering (SPS) is a relatively novel PM technique, which provides a rapid densification route and with the assistance of an applied compaction pressure. This process has shown significantly improved consolidation efficiency over more conventional PM-oriented sintering technologies. However, fundamental investigations are still lacking in terms of the fundamental processing parameters for a range of materials, particularly the sintering responses of titanium-based alloys. The current study examines a variety of processing factors, including the starting powder characteristics (i.e. particle morphology and size), and the sintering parameters (i.e. temperature, ramp rate and hold time). Two commercially pure grade titanium powders (i.e. sponge and hydride-dehydride (HDH)), and a lab produced pre-alloyed titanium aluminide powder, were sintered using the SPS technique to acquire a fundamental understating of the process. The effects of processing variables on the densification response, microstructure and hardness properties will be reported.