Characterization of hot deformation behavior of Haynes230 by using processing maps

The hot deformation characteristics of Haynes230 has been investigated in the temperature range 1050-1250 °C and strain rate range 0.001-10 s^-1 using hot compression tests. Power dissipation map for hot working are developed on the basis of the Dynamic Materials Model. The map exhibits two domains of dynamic recrystallization (DRX): one occurring in the temperature range of 1200-1250 °C and in the strain rate range of 0.001-0.03 s^-1, which associated with grain coarsening; the other occurring in the temperature range of 1100-1200 °C and strain rate range of 0.001-0.01 s^-1, which are the optimum condition for hot working of this material. The average apparent activation energy for hot deformation is calculated to be 449 kJ/mol. The material undergoes flow instabilities at temperatures of 1050-1100 °C and at strain rates of 1-10 s^-1, as predicted by the continuum instability criterion. The manifestations of the instabilities have been observed to be adiabatic shear bands which are confirmed by optical observation.