Deformation Resistance and Shape Change of Dispersed Fine Voids during High-Temperature Compression Deformation in Carbon Steel

Carbon steels with and without dispersed fine voids, the void diameter was ranging about 3~5 μm, were deformed in compression at elevated temperatures and at some strain rates. The deformation behavior depended on the testing conditions and the steel whether containing voids or not. The peak stress and the peak strain of the carbon steel with voids became higher compared with those of without voids. Occurrence of dynamic recrystallization (DRX) was, therefore, a little delayed by the presence of voids. Furthermore, the yield stress and steady state stress in the steel with voids appeared higher than those without voids. The shape and the distribution of voids drastically changed depending testing condition, i.e., the void size and the aspect ratio become smaller with decreasing strain rate and with increasing temperature. These observed phenomena were discussed in relation with DRX, grain boundary migration, grain boundary sliding and relaxation, etc.