On the high temperature deformation behaviour of titanium alloy BT3-1

摘要

BT3-1 (Ti-6Al-2.5Mo-l.5Cr-0.5Fe-0.3Si) is a α+ β titanium alloy that has been developed to meet the mechanical property requirements up to a temperature of 450 ℃. The high temperature deformation behaviour of the material was evaluated by carrying out isothermal hot compression tests in the α+ β, near β and β phase fields with a range of constant true strain rates. Using the flow behaviour data, processing map based on dynamic materials modeling was developed and the various domains in the map were correlated with microstructural mechanisms observed in the material. The material exhibits superplasticity when processed in the α+ β regime while it experiences dynamic recrystallization (DRX) of β phase when processed above the β transus. When deformed close to the p transus, the material exhibits partial β recrystallization where the migrating boundaries of the β phase are pinned by the fine globular α particles distributed in the matrix. The activation energy and activation volume for deformation was evaluated to ascertain the rate controlling deformation mechanism. The results obtained are presented and discussed here