OS1308 Influence of Deformation Induced Martensite on the Corrosion Fatigue Life of SUS304 Steels in 3% NaCl solution

Abstract

Metastable SUS304 steels were cyclically deformed in tension/compression in aqueous 3%NaCl solution in order to clarify the influence of deformation-induced-martensite (DIM) on the corrosion fatigue life in a pitting-forming environment. The number of cycles to failure, N_f increased with decreasing plastic strain amplitude, dε_<p1>. However, under dε_<p1> of 0.3%, the N_f increased in higher rate in terms of dε_<p1>. DIM was not detected after the fatigue test at dε_<p1> smaller than 0.3% while the volume fraction of DIM increased with increasing dε_<p1> at higher than 0.3%. Pitting was observed after the fatigue tests at dε_<p1> larger than 0.4% and increased with increasing DIM, suggesting that the formation of pitting was caused by DIM. Thus, the formation of DIM facilitates pitting and reduces corrosion fatigue life.