Larson-Miller correlation for the effect of thermal ageing on the yield strength of a cold worked 15Cr-15Ni-Ti modified austenitic stainless steel

For 20% cold worked 15Cr-15Ni-Ti modified austenitic stainless steel (Alloy D9), the Larson-Miller parameter can be used to describe the effects of prior thermal exposures to different time-temperature combinations on the 0.2% yield stress σ YS, ultimate strength and total elongation in subsequent tensile tests at 300, 723 and 923 K. A single master plot for all the tensile test temperatures was obtained by plotting the Larson-Miller parameter against the ratio S YS=(σ YS of thermally aged material)/(σ YS of un-aged material) at identical tensile testing temperature