The deformation instability and stability analysis of Ti-17 powder compact during thermo-rnechanical processing

The deformation instability and stability of Ti-5Al-2Sn-2Zr-4Mo-4Cr (Ti-17) powder compact prepared through argon atomization and hot isostatic pressing was characterized using hot processing map. Based on hot compression experiments, the hot processing map of Ti-17 powder compact was established at temperatures from 810 degrees C to 920 degrees C and strain rates from 0.001 s(-1) to 1 s(-)1. The deformation instability and stability regions of Ti-17 powder compact under different deformation conditions were identified. The deformation instability regions mainly focuses at temperatures from 817 degrees C to 927 degrees C and strain rates from 0.05 s(-1) to 1 s(-1), in which the maximum efficiency of power dissipation just reaches 0.35. The instability manifestations in adopted deformation conditions mainly are local large deformation, inhomogeneous deformation, internal crack, and deformation heating. The peak efficiency of power dissipation with the value of 0.6 in deformation stability regions corresponds to large dynamic recrystallization. The different efficiency of power dissipation in deformation stability regions could be used as a basis for selecting proper thermo-mechanical processing parameters to obtain different microstructure morphology according to the performance of the material. (c) 2012 Elsevier B.V. All rights reserved.