Examination of α′′, α′ and ω phases in a β-type titanium-niobium metal

Abstract

In this study, titanium-niobium (Ti-Nb) alloy samples containing β, α′′, ω and α′ were used to investigate the effect of each phase on the mechanical properties. The results show that the content of each phase affects the shape of the tensile curve. When the fraction of ω phase is relatively large, the tensile curve exhibits obvious upper yield point and lower yield point. However, the fraction of α′′ phase is relatively large; the tensile curve has a single peak yield stage. A small amount of α′ phase can significantly improve the yield strength, however, the elongation decreased significantly. In addition, some ω phase surrounded in α′′ matrix was also observed, and it can be inferred that the micro-crack may first appear at the incoherent ω/α′′ interface under the application of external stress.