New dislocation dissociation accompanied by anti-phase shuffling in the α ''martensite phase of a Ti alloy

Martensite phase plays a crucial role in the shape memory effect and superelasticity. In this study, a new dislocation dissociation was found in the alpha?? martensite phase of a Ti-based biomedical shape memory alloy by systematic transmission electron microscopy analysis and first-principles calculations. The slip direction of dislocation was along ( 101 ) , which was recently found in a single-crystalline martensite fab-ricated using stress-induced martensitic transformation. The ( 101 ) dislocation dissociated into two partial dislocations, and the Burgers vector for both partial dislocations was equal to 1/2 < 101 > . A planar fault with an anti-phase shuffling of basal plane was observed between the dissociated partial dislocations. The dissociation reaction of the ( 101 ) dislocation was summarized as ( 101 ) & RARR; 1/2 < 101 > + anti-phase shuf-fling boundary + 1/2 < 101 > . Most of the observed dislocations were in the form of screw dislocations, and the dissociated partial dislocations were twisted around the dislocation line.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, a new dislocation dissociation phenomenon was found in the alpha?? martensite phase of a Ti-based biomedical shape memory alloy, which contributes to the understanding of shape memory effect and superelasticity.