Physical Meaning of the New Creep Rupture Equation for Heat Resisting Steels

Abstract

The authors have proposed a new creep rupture equation assuming a thermally activated process for dislocation motion. The activation energy and the activation volume of the new equation have been formulated on the base of a dislocation model. The residual dislocation density, ρ r , the gliding distance of movable dislocations, g, and the equivalent obstacle spacing, d/p, where d is the obstacle spacing and p is a characteristic parameter of the obstacles, can be directly estimated using the creep rupture data with some assumptions but without any adjustable parameters. The values of d/p and g are comparable with the reported particle spacing and the width of sub-boundaries, respectively. The estimated dislocation densities are consistent with the observed values in the literature. The values of g decreases and d/p increases with increasing both test temperature and time to rupture. If dynamical aging and/or precipitation occur, d/p should be decreasing.