Abstract
In order to study the effects of vacuum environment on high temperature low-cycle fatigue properties of Inconel 617, a set of strain controlled fatigue tests were carried out at 1000°C in air and vacuum environments.
The fatigued specimens were metallographically examined by means of optical and scanning electron microscopies and electron probe microanalysis.
The following conclusions were obtained:
(1) The low-cycle fatigue life decreased as follows; in air<in poor vacuum (≅1.3Pa)<in vacuum (≅2×10-2Pa).
(2) The difference of fatigue lives in air and in vacuum environments tended to become smaller for the specimen with coarser grains.
(3) The environmental dependence of fatigue life can be explained based on the property of oxide scale, decarburization and internal oxidation behaviors, and the crack propagation rate.
