Flow behavior and dynamic transformation of bimodal TC17 titanium alloy during high strain rate hot compression

The flow behavior and dynamic transformation of near beta TC17 alloy with a bimodal structure were investigated by hot compression with the high strain rate range from 1 s-1 to 20 s-1 and in the temperature range from 840 degrees C to 900 degrees C in this study. The most evident discontinuous yielding and post strain hardening occur at 840 degrees C-20 s(-1 )due to its high alpha p volume fraction before compression and the subsequent strong work hardening effect. High strain rate can slightly promote dynamic transformation when alloy is compressed at 840 degrees C and 870 degrees C due to domination of the high flow stress and temperature raising. However, more dramatic dynamic transformation is obtained for 1 s(-1) at 900 degrees C because the deformation heating at higher temperature/lower strain rate is less evident, and the deformation time thus maters more greatly on the phase transformation. The fine alpha s shows an obvious phase transformation priority than the coarse alpha p under all conditions due to the enhanced alloy element (Al) diffusivity resulting from enlarged alpha/beta interface and higher dislocation (diffusion channel) density around it. The alpha p promotes the dynamic re crystallization of beta phase while this effect becomes weaker when dynamic transformation is progressed greatly, mainly due to the inevitable stored energy consumption and reduced alpha p volume fraction caused by phase transformation. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

The flow behavior and dynamic transformation of near beta TC17 alloy with a bimodal structure were studied using hot compression. The results showed that discontinuous yielding and post strain hardening were most pronounced at 840°C-20 s-1. High strain rate slightly promoted dynamic transformation at 840°C and 870°C, while more dramatic dynamic transformation occurred at 900°C and 1 s-1.