Cost-Effective Production of High-Property Titanium Alloy from Powder

Abstract

Blended Elemental Powder Metallurgy is a very attractive method for producing titanium alloys, which can be formed near net shape and have freedom in composition selection. However applications are still limited due to affordability. In this paper, we will discuss a possible cost-effective route, combining vacuum sintering, extrusion, and heat treatment, to produce titanium alloys with similar or better mechanical properties than that of ingot metallurgy titanium alloys. The as-processed material with an oxygen content of 0.34 ± 0.005 wt.% was subjected to heat treatments such as β annealing plus ageing and α+β annealing without ageing to attain a typical lamellar/Widmanstätten/basketweave type structure with a large variation in terms of the microstructural features such as grain size, colony size, inter-lamellar spacing, thickness of grain boundary α, and size of individual lamellar. From mechanical property data attained here, it was apparent that annealing in high α-β region gave a much better combination of mechanical properties: yield strength (860-902 MPa), ultimate tensile strength (1060-1084 MPa) and ductility/plastic strain (11.5-13.6%). The hardness values of heat treated material varied between 346-376 Vickers hardness (36.8-44.5 Rockwell hardness).