Effects of Dynamic Strain Aging on the Strength of 18–8 Type Austenitic Stainless Steel

Abstract

The effects of dynamic strain aging (DSA) on the tensile and smooth rotating fatigue strength of 18-8 type austenitic stainless steel at room and elevated temperatures were investigated. The strain aging temperature range was from 300 to 923K and the tensile strain rate was 5×10-4s-1. The data obtained indicate that: i/ DSA or static strain aging (SSA) produced a substantial increase in yield strength at both room and elevated temperatures in respect to solid solution (SS) specimens as well as cold-working (CW) specimens, while maintaining as appreciable ductility, which is 10-20% higher than that of CW specimens at room temperature or is the same as that of CW specimens at elevated temperature; ii/ the smooth rotating fatigue strength at room temperature after DSA was increased evidently than that of SS specimens; iii/ both the tensile strength and fatigue strength will increase with prestrain and strain temperature. All these results are explained in terms of the interaction between the moving dislocations and the diffusing solute atoms and the morphology and the distribution of the dislocation in the strain-aged alloy.