Deformation Mechanism and Constitutive Consideration for Ti-5Al-5Mo-5V-3Cr-1Zr Alloy Compressed at Elevated Temperatures

摘要

To investigate hot deformation behavior of a Ti55531 alloy, a series of isothermal compression tests were performed on a Gleeble-3500 simulator at the temperature range of 1033-1153 K and constant strain rates of 0.001-1 s(-1). Based on the experimental flow stress data, processing map and grain morphology, the deformation mechanism map was summarized. In this study, the dominant microstructural mechanism processed near or above beta-transus temperature was considered to be deformation characteristic of beta phase, where dynamic recovery was in dominant and at mediate strain rate dynamic recrystallization was also observed. Superplasticity was found at 1003-1033 K and 0.001 s(-1), correlating with dislocation glide and grain boundary slide (GBS). Undesirable plastic flow such as flow localization and flow rotation was found at high strain rate of 0.1-1 s(-1)and at the entire test temperature range. The optimum working window of this alloy was finally obtained at 1003-1063 K and 1093-1153 K and at 0.001-0.1 s(-1).