Microstructural evolution of a Ti-4.5Al-3Mo-1V alloy during hot working

Abstract

The study investigated the variation of microstructure of a Ti-4.5AL-3Mo-1V alloy during hot compressing in α + β phase field. By scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we systematically examined the influences of hot working parameters on the microstructural features including of the morphology of α grain, volume fraction of α phase and dynamic recrystallization (DRX). The experimental evidence showed that both α and β phases underwent DRX under the experimental conditions. Moreover, the recrystallization degree of α phase was more sufficient than that of β phase. The DRX was accelerated with increase of deformation temperature and decrease of strain rate. It was also noted that a certain degree of the (α → β) phase transformation occurred concurrently with the mechanical deformation. In accordance with the microstructural evolution, flow curves of the alloy were characterized by a linear increase until regular oscillations at high strain rates or single peak at low strain rates and softening was followed.