High-Temperature Low Cycle Fatigue Crack Propagation and Life Laws of Smooth Specimens Derived from the Crack Propagation Laws

Abstract

The objectives of this work are (1) to make clear the behavior of high-temperature low-cycle fatigue (LCF) crack propagation, (2) to verify the applicability of the J-integral to the fracture mechanics equations of crack propagation rates, (3) to derive two types of LCF life laws of smooth specimens based on the two types of crack propagation equations (i.e., cycle-dependent and time-dependent), (4) to show a resemblance to or a difference from the Manson-Coffin equation and the strain-range partitioning equations, and (5) to characterize the cycle-dependent and time-dependent fatigue laws. The effectiveness of the proposed failure-life equations was examined using experimental data on isothermal and thermal fatigue of smooth specimens.