Physical significance and reliability of Larson–Miller and Manson–Haferd parameters

Abstract

Both the Larson–Miller and the Manson–Haferd parameters are used to extrapolate rupture data from high temperature creep. The first of these is in agreement with the theoretical equation for low temperature deformation only, and cannot describe the high temperature properties accurately. The second parameter has no physical basis. Starting from data taken from a theoretical stress–rupture time diagram, both extrapolation methods are tested. At the lower stresses the Larson–Miller method considerably overestimates the resistance of the material to rupture. Despite the lack of physical significance, the Manson–Haferd parameter coincidentally describes to some extent the complex deformation patterns due to the different deformation mechanisms, and is more reliable for high temperature predictions.

MST/1882