Effects of TiC and Cr23C6 carbides on creep-fatigue properties in AISI 321 stainless steel

Abstract

In order to investigate the effects of TiC and Cr23C6 carbides on creep-fatigue behaviors, total strain range controlled creep-fatigue tests of TiC and Cr23C6 aged AISI 321 stainless steels with the same carbide density at the grain boundary were conducted at 600°C. It is observed that creep-fatigue life of TiC aged alloy is longer than that of Cr23C6 aged alloy in the same test conditions. To verify the origin of the difference in creep-fatigue life between the two alloys, microstructural observations are conducted by scanning electron microscope (SEM) and transmission electron microscope (TEM). It is understood to be due to the strong cavitation resistance of TiC aged alloy compared with that of Cr23C6 aged alloy. It is considered that formation and growth of cavities are retarded by strong interfacial affinity between TiC and matrix.