Dynamic strain ageing in prior cold worked 15Cr–15Ni titanium modified stainless steel (Alloy D9)

Dynamic strain ageing (DSA) behavior of a 20% prior cold worked titanium modified austenitic stainless steel (Alloy D9) was investigated in the temperature range 300–1023 K at a constant (nominal) strain rate of 1.33 × 10−3 s−1. Serrated plastic flow was observed in a narrow temperature region of 773–873 K. Anomalies characteristic of DSA were observed in the variations of strength, ductility, and strain hardening parameters with temperature. Specifically, the difference between ultimate tensile stress and yield stress indicated that a single DSA mechanism is operative over the range of observations. Plastic strain energy density for uniform deformation showed a peak in the DSA temperature range, suggesting that in this material, DSA should enhance the ductile fracture resistance.