Dynamic Restoration Process of Ni-30Fe Alloy during Hot Deformation

Abstract

Change in deformed microstructure with dynamic restoration at various strain, strain rate and deformation temperature was examined for a Ni-30Fe alloy during hot deformation. A screw embedded specimen is used for quantitative evaluation of the distribution of compressive strain in the hot compressed specimen. A typical microstructural evolution due to dynamic recrystallization is observed at a deformation temperature of 1 173 K at a strain rate of 10/s and at 1 073 K and 1 173 K at a strain rate of 0.1/s. On the other hand, when the compressive strain exceeds 3.2, a characteristic microstructure consisting of equiaxed recovered grains is developed at a deformation temperature of 973 K at a strain rate of 0.1/s and at deformation temperatures of 973 K and 1 073 K at a strain rate of 10/s. The interpenetration of the serrated austenite grain boundaries, so-called geometric recrystallization, is thought to be responsible for microstructural evolution of the equiaxed recovered grains.