Effect of temperature and strain rate on tensile flow and work hardening behaviour of a Ti modified austenitic stainless steel

Abstract

The tensile flow stress data for a 15Cr - 15Ni - 2.2Mo - Ti modified austenitic stainless steel in the temperature range 300 - 1023 K and in the strain rate range 6.3 × 10^-5- 1.3 × 10^-2 s^-1 was analysed in terms of the Ludwigson and Voce equations. It was found that the Ludwigson equation described the flow behaviour adequately up to the test temperature of 923 K, whereas the Voce equation could be employed over the full temperature range. The peaks/ plateaus observed in the variation of these parameters as a function of temperature and strain rate in the intermediate temperature range have been identified as one of the manifestations of dynamic strain aging (DSA). Also the variation of these parameters with temperature and strain rate could clearly bring out the different domains of DSA observed in this alloy. The work hardening analysis of the flow stress data revealed that, in the DSA regime, the onset of stage III hardening is athermal.