Study on Extremely-Low-Cycle Fatigue of Fe–15Mn–10Cr–8Ni–4Si Alloy

The extremely-low-cycle fatigue behavior and post-fatigue microstructure of an Fe–15Mn–10Cr–8Ni–4Si austenitic alloy were investigated under a strain rate maximum amplitude 0.5%/s 10%, respectively, in the axial direction. results can be summarized as follows. (1) A steel damper made withstand approximately 15 swings back even if structure is distorted by 10% due to large earthquake. (2) εpa–Nf relationship demonstrated linear relationship, it was confirmed that Manson-Coffin rule holds. (3) Even test with 0.5%/s, specimen temperature did not exceed 40°C all conditions. Therefore, ε phase formed (4) Various facets secondary cracks observed propagation region fracture surface. Accordingly, inferred most main propagated at γ/ε interface merged. Consequently, crack could propagate linearly, generation caused decrease displacement tip when stress redistributed, thus extending life.