High Temperature Plastic Instability and Dynamic Strain Aging in the Tensile Behavior of AISI 316 Stainless Steel

The plastic instability in the stress-strain curve and work hardening of a type AISI 316 austenitic stainless steel was investigated in the high temperature range of 150°C to 800°C for two strain rates. The results indicate the occurrence of plastic instability and serrations between 200°C and 650°C with peaks in both the tensile strength and work hardening rate. These plastic instability/serrations are associated with dynamic strain aging behavior. As a consequence, within the temperature interval of plastic instability, a negative value for the strain rate sensitivity was found. Based on the activation energy, it is proposed that a mechanism of substitutional solute atoms interaction with dislocations be responsible for the plastic instability.