Influence of dynamic restoration mechanisms on the hot workability of Waspaloy and concentrated FCC alloys

Abstract

During torsional deformation in the temperature range BOO-1200°C, and strain rate range 0.1-7.0 s-1, Waspaloy exhibited high strain hardening and low ductility up to 950°C and rapidly rising ductility above that, as a result of undergoing dynamic recrystallization. Above 950°C, the strain rate was related to the stress exponentially and to the temperature through an Arrhenius relationship with an activation energy of 410 kJ/mole. Microstructural studies showed that dynamically recrystallized grains formed, containing a substructure which persisted without change in dimension during the steady-state region. The dynamic recrystallization resulted in a movement of the grain boundaries away from the cracks and pores, thus slowing down their growth and providing high ductility.