Structure evolution mechanism and physical modeling of Ni60Ti40 during dynamic recrystallization.

The steady-state rheological stress, critical strain capacity, structure evolution dynamics, and energy dissipation during dynamic recrystallization of Ni60Ti40 alloy were characterized through single-pass isothermal compression experiments at 980–1070 °C and strain rate of 5 × 10−3 - 5 s−1. The underlying structural evolution mechanism was revealed via microstructure characterization. The critical strain capacity of Ni60Ti40 during dynamic recrystallization decreased and the structure transformation volume fraction increased with the rise of deformation temperature or the decline of strain rate. The critical power dissipation rate upon dynamic recrystallization was 0.15. At low temperature and high strain rate, the structure evolution was dominated by geometrical dynamic recrystallization. At high temperature and low strain rate, non-continuous dynamic recrystallization was dominant. The nucleation mechanism was grain boundary slip induced by dislocation motion. • The rheological stress, critical strain capacity and structure evolution dynamics of Ni60Ti40 during dynamic recrystallization were revealed. • The KM model, Poliak-Jonas critical strain model, and Avrami recrystallization volume fraction evolution model were introduced into the power dissipation rate model. Thereby, the energy changing rules of Ni60Ti40 during dynamic recrystallization were clarified. • Single-pass thermal compression simulation tests under different deformation conditions were designed. The structure evolution mechanism of Ni60Ti40 during dynamic recrystallization was uncovered through microstructure characterization. [ABSTRACT FROM AUTHOR]