Transformation of Retained Austenite and Observation of Cracks under Low-Cycle Fatigue Testing

概要

論文の詳細を見る
The low-cycle fatigue properties of quenched and tempered 0.17%C-21%Ni steel which contains about 18 and 27 volume percent of retained austenite were investigated mainly by the X-ray diffraction technique. The fatigue tests were carried out at 20℃ under constant total bending strain ranges of ±0.9, ±1.3, and ±1.6% with zero mean strain. The results obtained are summarized as follows : (1) The strain-induced transformation of retained austenite depends not only on the strain range but also on the tempering temperature. (2) Stability of retained austenite during fatigue test is maximum in the specimens tempered at temperatures between 250 and 350℃. This dependence of the austenite stability on the tempering temperature is similar to that of stabilization for subzero treatment. (3) The changes of half-value breadth, the particle size and microstrain in martensite during fatigue tests are quite similar as well in the martensitic steels containing 18 and 27 volume percent of retained austenite as in medium carbon martensitic steel without retained austenite. (4) The values of half-value breadth, particle size and microstrain in martensite phase are various in any stage of strain cycling dependent on the tempering temperature and strain range. Therefore, these values are at the present time far from adequate to be taken for the reliable estimate of the fatigue damage in martensitic steel. (5) Fatigue microcracks formed at the early stage of crack formation, are observed not only at non-metallic inclusions and in prior austenite grain boundaries, but along the edges of martensite leaves. Growth of these microcracks is sometimes prevented by their crossing to other martensite leaves or prior austenite grain boundaries.
東北大学の論文

Transformation of Retained Austenite and Observation of Cracks under Low-Cycle Fatigue Testing

スポンサーリンク

概要

著者

関連論文

スポンサーリンク