Abstract
A fatigue strength diagram, applied to the estimation of fatigue strength under mean stress or residual stress, is not obvious in case of aluminum alloys because they do not have endurance limit-especially at high temperature. Thus, we make up the generalized fatigue strength diagram at N cycles of aluminum alloy at high temperature, using the strength at N cycles instead of the endurance limit, and divide the single line into the multiple ones by fracture feature; typical fatigue failure, failure with plastic deformation and the one with creep. In this study, we formulate the constitutive equations for this set of the fatigue strength curves at N cycles. Both the line for typical fatigue failure and the one for failure with plastic deformation are expressed as straight lines. The one for failure with creep is expressed as straight line or curve, which is dependent on creep mode.
