Influencing parameters on martensite transformation during low cycle fatigue for steel AISI 321

The influence of the low cycle fatigue parameters strain amplitude, cycle number, test temperature and frequency on the formation of martensite was investigated. Linear dependencies of the martensite content on plastic strain amplitude and the cycle number were found. The martensite content decreases exponentially with increasing temperature. No influence of LCF test frequency was found. The susceptibility for the martensitic transformation strongly depends on the thermo-mechanical pretreatment. No significant residual stresses were found after cyclic loading.