Creep–fatigue interaction behaviour of a 15Cr–15Ni, Ti modified austenitic stainless steel as a function of Ti/C ratio and microstructure

The creep–fatigue interaction behaviour of a 15Cr–15Ni, Ti modified austenitic stainless steel has been characterized as a function of Ti/C ratio and microstructure. Creep–fatigue interaction behaviour has been investigated in this material, by introducing hold times with durations ranging from 1 to 10 min at peak tensile strain. The material was tested at 923 K in Ti/C ratios of 4 and 8 and in the solution annealed, cold worked and aged conditions. It has been ascertained that precipitation controls creep–fatigue interaction properties in this alloy. Carbides which precipitate on the grain boundaries in the solution annealed material are found to be beneficial to creep–fatigue interaction properties, while fine titanium carbides which precipitate in the matrix in cold worked and aged conditions of the alloy, have been found detrimental to creep–fatigue interaction properties.