Mechanism of α → β dynamic transformation in commercial pure titanium deformed at high temperature below β-transus

A counterintuitive strain-induced alpha -> beta dynamic transformation of commercial pure titanium deformed at a temperature below the beta-transus was investigated. It was revealed that the serrated-shaped beta phase first formed at grain boundaries and then grew into a grains. Finally, the initial equiaxed a grain was transformed into a (alpha + beta) lamellar structure. The development of beta phase laths was controlled by moving dislocations in the a phase, and both were affected by the diffusion of beta-stabilizing elements. Furthermore, the redistribution of Fe in CP-Ti resulted in a special reversal transformation of beta -> alpha in the isothermal holding period after deformation. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the counterintuitive strain-induced alpha -> beta dynamic transformation of commercial pure titanium deformed at a temperature below the beta-transus. It was found that the serrated-shaped beta phase first formed at grain boundaries and then grew into grains, eventually transforming the initial equiaxed alpha grain into a (alpha + beta) lamellar structure. The development of beta phase laths was controlled by moving dislocations in the alpha phase, and both were influenced by the diffusion of beta-stabilizing elements. Moreover, the redistribution of Fe in CP-Ti resulted in a special reversal transformation of beta -> alpha during the isothermal holding period after deformation.