TEMPERATURE-DEPENDENCE OF THE DISSOCIATION WIDTH OF DISLOCATIONS IN A COMMERCIAL 304L STAINLESS-STEEL

The dissociation width of dislocations in a commercial AISI 304L stainless steel was measured as a function of temperature. Two types of experiments were carried out. In one, specimens were deformed at room temperature, followed by annealing at various temperatures, and in the other, specimens were deformed directly at various temperatures. In both experiments the width of near-edge dislocations remained unchanged upto 300-400-degrees-C, then decreasing gradually. On the other hand, the width of near-screw dislocations showed the maximum at around 400-degrees-C, when specimens were deformed directly at high temperatures: When specimens were deformed at room temperature and then annealed at high temperatures, the maximum was less evident. The Suzuki segregation was invoked to explain behaviour of the dissociated dislocations in a commercial AISI 304L stainless steel. It is proposed that some typical features of dynamic strain ageing observed at around 400-degrees-C such as enhanced work hardening and planar slip could be caused in part and in conjunction with other more effective mechanisms than those caused by the slightly enhanced dissociation width of near-screw dislocations in the same temperature range.