Abstract
In order to clarify the fatigue mechanisms in stainless steel, three kinds of stainless steels were fatigued and their substructures were observed by transmission electron microscopy. The following results were obtained:
(1) In fatigued 18Cr-40Ni-1.7Mo and 18Cr-8Ni-1.7Mo stainless steels, cell structures are formed and they contain many dislocation loops.
(2) In fatigued 18Cr-8Ni stainless steel (SUS 27), fatigue cracks propagate along intense slip bands.
(3) In fatigued 18Cr-8Ni-1.7Mo stainless steel, extrusions and intrusions in slip bands are observed at the edge of thin foils.
(4) Although much martensite is formed by cold rolling of few per cent in 18Cr-8Ni-1.7Mo stainless steel, no martensite is formed by fatigue of low stress amplitude.
