Internal stresses and stored energy density in the grains at deformation of FCC-polycrystal

Abstract

The distribution of internal stresses and the density of the accumulated energy in the deformed polycrystal austenitic steel were investigated. The internal stresses and the accumulated energy density were determined using the bend extinction contours observed on the deformed steel micrographs. The laws of internal stresses distributions and the accumulated energy density in the grains with various bending types were determined. At the deformation degrees ε = 14 % and ε = 25 % the average values of internal stresses and the accumulated energy density inside the individual grains with compound bending were higher than in the grains with simple bending. It testified the fact that the grains with compound bending were more stressed. At the increase of the steel deformation degree up to ε = 25 % the growth of contributions from additional modes observed on the internal stress distributions slowed down and at ε > 25 % the average internal stress decreased. The relaxation of internal stresses was due to the origin and increase of the microtwins volume fraction at the austenitic steel deformation. The presence of microtwins influenced the distributions of internal stresses and the accumulated energy density in the deformed polycrystal austenitic steel.