A Comprehensive Creep Model

Based on Dorn’s creep theory, a comprehensive creep model has been developed that is applicable to the calculation of deformation processes at steadily increasing temperatures and slowly varying load. It is shown that the entire course of the creep curve (excepting the tertiary creep) of structural (polycrystalline) materials is uniquely determined by two stress-dependent parameters, ε_t0 and Z. Explicit expressions for the description of creep processes are proposed. These expressions cannot strictly be regarded as equations of state, but yield an accuracy acceptable for engineering calculations even if dσ/dt ≠ 0.