Determination of critical parameters for dynamic recrystallization in Ti–6Al–2Zr–1Mo–1V alloy

The true stress—strain curves of Ti–6Al–2Zr–1Mo–1V alloy were achieved by a series of isothermal compression tests with height reduction of 60% under the deformation temperatures of 1073–1323 K and the strain rates of 0.01–10 s−1. The critical conditions for the onset of DRX were attained when the value of |−dθ/dσ|, where strain hardening rate θ = dσ/dɛ, reached the minimum which corresponds to an inflection of θ versus σ curve. Thus, two important potential parameters, critical strain and critical stress, were identified, and expressed as σc/σp=0.37−0.60, σc/σp=0.81−0.91. Furthermore, by the regression analysis for conventional hyperbolic sine equation, the main material parameters such as α, β, n, and DRX activation energy, Q, were calculated. In addition, the evolution of Q with strain rate and temperature was revealed as a 3D response surface.