Kinetics equations and microstructural evolution during metadynamic recrystallization in a nickel-based superalloy with δ phase

The metadynamic recrystallization (MDRX) characteristics of a nickel-based superalloy with delta phase are studied by isothermal two-pass hot compressive experiments. The kinetic equations are developed to evaluate the softening fractions caused by MDRX. The microstructural changes induced by MDRX are investigated using interrupt experiments and quantitatively characterized by microscopic observations. It is found that the softening fraction significantly increases with increasing the pre-strain, strain rate and deformation temperature. The evaluated softening fractions well agree with the tested ones, which demonstrates that the developed kinetic equations can accurately evaluate the MDRX fractions for the investigated superalloy. Additionally, the MDRX grain size sharply increases when the pre-strain and deformation temperature are increased, while obviously decreases with increasing the strain rate. (C) 2016 Elsevier B.V. All rights reserved.