Fabrication of titanium-based composites by spark plasma sintering and crystallization of the amorphous phase

Improvement of strength and ductility of titanium alloys is a significant and eternal topic in development of advanced structural materials. To date, improved strength and ductility for titanium alloys can be achieved in amorphous structure and nano/ultrafine/fine-grained size regime obtained by several kinds of materials forming methods. In this chapter, a material forming method by coupling spark plasma sintering with crystallization of amorphous phase, fabricating titanium alloys with excellent mechanical properties, was reviewed systematically. By appropriate annealing of sintered amorphous alloy in bulk form prepared from spark plasma sintering at the supercooled liquid region of a mechanically alloyed amorphous alloy powder, crystallized phase with controllable grain size, phase morphology and distribution can be precipitated from the amorphous phase (or sintered amorphous alloy), and therefore, titanium alloys with matrix of amorphous phase or crystallized phase as well as improved strength and ductility were obtained. Meanwhile, sintering parameters affect significantly microstructure and mechanical property of fabricated bulk titanium alloys. Facture mechanism of fabricated titanium alloys under stress was explained based on a proposed Developed Hard-soft Model . The results obtained provide a promising method for fabricating large-sized crystallized phase-containing bulk titanium alloys with excellent mechanical property by powder metallurgy