BCC stabilization and growth stress behavior in Ti/V multilayers

As the length scale decreases, materials can undergo size-dependent phase changes. This work explores the hcp to bcc Ti transformations in Ti/V multilayers of equal volume fraction. A series of Ti/V multilayers were sputter-deposited and revealed a transition at ~ 1 nm Ti. This length scale stability is explained through a series of in situ growth stress measurements that are correlated to the epitaxial orientation of the Ti and V growth directions with respect to each other within the multilayer. It was found the hcp Ti undergoes in-plane compression while bcc V undergoes in-plane tension. It is believed that the interplay of large misfit strain and the surface energy driven intermixing, quantified by atom probe tomography, contributes to the stabilization of bcc Ti.