A fixed point in the Coffin–Manson law

It is assumed that the Coffin–Manson law exhibits a fixed point at varying fatigue ductility exponent for given series of tests. This provides for the law three constants, the bilinearity characterised by a change of fixed point and exponent and, at stage I and through a length scale, the expressions of the constants of a kinetic equation of the crack. The results are addressed to observations in austenitic stainless steels of the literature and discussed in term of microstructures determining the type and propagation mechanism of the crack measured by the fixed point and exponent, respectively.