Effect of phase stability on local mechanical behavior in beta type titanium alloys

In general, the elastic modulus of a metallic material is proportional to the mechanical strength. A multi-functional beta titanium alloy, Gum Metal has been developed to have both low modulus and high strength after severe cold working. However, both its underlying mechanisms for multi-functional characteristics and its deformation mechanism have not yet been elucidated. In this study, nano-indentation and in-situ compression test in TEM have been performed to investigate the effect of phase stability on local mechanical behavior. We have examined the local mechanical behavior in Ti-18Mo alloy which has a higher bcc phase stability than Gum Metal. Nano-indentation tests revealed that the phase stability does not affect the local dynamic behavior. On the other hand, in situ compression test confirmed the effect of phase stability on the local mechanical behavior. Dislocation motion has been observed in Ti-18Mo alloy by in-situ compression tests in TEM, although such dislocation activity was not observed in Gum Metal in our previous study. © 2020 Japan Institute of Light Metals. All rights reserved.