1993 Volume 79 Issue 2 Pages 219-226
Creep deformation and fracture mechanisms are known to change with stress and temperature, as indicated in the deformation and fracture mechanism maps. When creep rupture data are evaluated with a time-temperature parameter (TTP), the data should be divided into several mechanism fields. This idea was applied to creep rupture data difficult to be described by a simple TTP and stress function. It was suggested that, by dividing rupture data, all data can be described by a TTP having only one arbitrary constant and a linear stress function. Within the same field, rupture lives hundred times longer than the longest test duration could be predicted without introducing any appreciable error. Extrapolation across a field boundary, however, caused serious error ; one may not correctly predict a rupture life two times longer than the test duration. Information about field boundaries is necessary for correct extrapolation.
