Mechanism of crack propagation in low cycle fatigue of type 316L stainless steel within the temperature range 20-300 deg C

Strain-controlled low cycle fatigue tests on type 316L austenitic stainless steel using uniaxial specimens have been conducted in the temperature range 20-300 deg C. A fixed strain rate of 1mult10 exp -3 s exp -1 and a total strain range varying between 0.4 and 1% were employed. A major finding is that there is a trough in the total fatigue life vs. temperature curve at high strain ranges and at temperatures in the region of 50 deg C, caused by cyclic cold creep. In this paper, we examine the microstructural characteristics of the region below the fracture surface during low cycle fatigue and propose a model which semiquantitatively explains the anomalous low cycle fatigue behaviour at 50 deg C. Copyright (c) 1995 Elsevier Science S.A. All rights reserved.