Processing, microstructure, properties and fracture behaviour of Ti-6Al-4V manufactured from pre-alloyed powder

This study investigates the consolidation of pre-alloyed Ti-6Al-4V powder through thermomechanical processing that involves cold isostatic pressing, sintering, hot pressing and extrusion. The microstructural evolution, oxygen pick-up and tensile properties attained after each major consolidation step reveal that there was a significant oxygen pick-up during de-binding/sintering, hot pressing had improved strength/ductility by eliminating porosity and extrusion resulted in a relatively fine lamellar structure. Overall, as-extruded material had an oxygen content of 0.22 wt-%, impact toughness of 21 J, yield strength of 971 MPa, ultimate strength of 1124 MPa and ductility of 9-11% which is comparable to corresponding values reported in the literature. An investigation of fracture surfaces along with crack propagation behaviour highlights that ductile fracture was the predominant mode of failure.