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 degrees 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 degrees 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 degrees 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 degrees 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. (C) 2008 Elsevier B.V. All rights reserved.