Hot deformation behavior of the Ti6A14V alloy prepared by powder hot isostatic pressing

Ti6A14V alloy have been prepared by powders HIP technology under 910(circle)C/120 MPa for two hours. Surface chemistry composition of Ti6A14V powders have been analyzed by XPS technology, results show that oxide layer exist on the surface of the Ti6AI4V powders. Microstructures of the HIPed alloy present a typical grid polygon structure which consist of the equiaxed grains and lamellar structures. And the lamellar structures are surrounded by the equiaxed grains which are formed through DRX process. Hot deformation behavior of the HIPed alloy was studied through a series of isothermal compression tests over the temperature range 645-1025(circle)C and strain rates range from 0.01s(-1) to 10s(-1). Hot processing maps and constitutive model were established based on the DDM model to give detailed information about hot deformation behavior. The activation energies for the alpha+beta phase and the single beta phase were estimated to be 365.5 kJ/mol and 447.8 kJ/mol, respectively. Microstructure evolutions of the samples after tests were observed. Results show that in the alpha+beta phase field, dynamic globularizations as well as platelet buckling/kinking are found to be the softening mechanisms at both lower and higher strain rates. However, in the single beta phase, DRX was found to be insufficient. (C) 2017 Elsevier B.V. All rights reserved.