1994 Volume 80 Issue 7 Pages 557-561
Solid solution hardening and softening of austenite, i.e. completely opposite phenomena, have been reported for plain carbon steel. These problems were studied in tension and compression tests for 0.05 to 0.84 mass % carbon steels. The shapes of dynamic recrystallization (DRX) type flow curves are almost independent of carbon content. Peak flow stress as well as steady state flow stress rapidly decrease with increase in carbon content and approach a certain value in high concentration, i.e. solid solution softening takes place in the range of higher strain. On the other hand, flow stresses in the range of initial work hardening rapidly increase and then go to a saturation, i.e. solid solution hardening occurs at lower strains. The solid solution softening for stresses at higher strain can be attributed to the enhanced DRX caused by increased diffusivity of vacancy due to the addition of carbon. In contrast, the solid solution hardening for stresses at lower strain may be caused by the increase of dragging stress for dislocation motion due to carbon atmosphere or excess vacancy.
