A new dynamic recrystallization mechanism in adiabatic shear band of an α/β dual phase titanium alloy: Composition redistribution

In this paper, the composition distribution characteristics in adiabatic shear bands (ASBs) of an alpha/beta dual phase Ti-5.5Mo-7.2Al-4.5Zr-2.6Sn-2.1Cr alloy and its influence on dynamic recrystallization (DRX) were investigated via atomic probe tomography. The results showed that in the ASB transition region, a clear grain boundary (GB) in alpha/beta interface was observed. However, in the ASB central region, a fuzzy GB was formed in alpha/beta interface, and abundant dislocations accumulated in the fuzzy GB. In addition, beta stabilizing elements (Mo/Cr) became rather sparse in some local regions of eta grains to form finer alpha grains, while in some regions of alpha grains, local beta stabilizing elements were enriched to form finer beta grains, thus separating the original grains into finer DRX grains. The unique composition distribution characteristics in alpha/beta grains and alpha/beta interface were defined as composition redistribution, which was the combined result of localized plastic deformation and adiabatic temperature rise. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

This paper investigates the composition distribution characteristics in adiabatic shear bands (ASBs) of an alpha/beta dual phase Ti-5.5Mo-7.2Al-4.5Zr-2.6Sn-2.1Cr alloy and its influence on dynamic recrystallization (DRX) using atomic probe tomography. The results demonstrate the formation of fuzzy grain boundaries in the ASB central region, with enriched beta stabilizing elements contributing to the formation of finer DRX grains. These unique characteristics, defined as composition redistribution, result from localized plastic deformation and adiabatic temperature rise.