Dynamic recrystallization behavior and mechanism of bimodal TC17 titanium alloy during high strain rate hot compression

This study investigates the dynamic recrystallization (DRX) behavior, grain structure and texture evolution of bimodal TC17 alloy during high strain rate (20 s−1) hot compression at 840 ℃ and 900 °C respectively. Results reveal that the lamellar αs contributes almost no help to the DRX of β phase at both temperatures due to its easier occurring of dynamic transformation. The αp induced particle stimulated nucleation (PSN) dominates the DRX of β phase at 840 °C but becomes auxiliary at 900 °C. The αp contributes to the formation of dense LAGB “cells” in β phase at 900 °C until 40% compression and then becomes the pinning point of DRX grain growth when the strain increases to 60%. The decomposition of αp at 840 °C is deeply related to the dislocation promoted continuous dynamic recrystallization, which is dominated by basal slip and followed with the participation of prismatic and pyramidal ones. In this way, the paralleled and subsequent net-like LAGBs are formed in αp. The texture intensity of both αp and β matrix decreases with increased DRX degree and 840 ℃ is the more favored deformation temperature for this alloy under high strain rate background due to its high DRX volume fraction (46.1%) of β phase and the uniform distributed αp.