Deformation behavior of carbon steel with dispersed fine voids at elevated temperatures

A carbon steel containing dispersed fine voids, with diameters in the range of 3–5 μm, was deformed in compression at temperatures between 1063 K and 1153 K and at true strain rates from 4.2 × 10−5 s−1 to 4.2 × 10−3 s−1. The deformation behavior did not differ much from that of a carbon steel without voids. The maximum stress and the corresponding maximum strain increased in the presence of a dispersion of voids, and, as a consequence the occurrence of dynamic recrystallization (DRX) was also slightly delayed. Furthermore, the yield stress and the steady-state stress increased by about 10%. The shape and distribution of voids changed depending upon strain, strain rate and temperature. With decreasing strain rate and increasing temperature, the aspect ratio of the voids decreased. These observed effect of voids on high temperature deformation behavior and the void shape change during deformation are discussed in relation with such mechanisms as DRX, grain boundary migration, grain boundary sliding and relaxation.