Calculation of the cyclic hardening curves of fatigued FCC monocrystals using a two‐phase model

Abstract

AbstractThe cyclic hardening curve of fatigued fcc monocrystals shows a maximum of the stress amplitude if the plastic resolved shear strain amplitude γap exceeds the threshold value γM for the formation of persistent slip bands (PSBs). Using a simple two‐phase model the typical shape of the cyclic hardening curve will be calculated for lower γap values. The calculation takes into account the fact that the PSB formation starts already at a „nucleation stress”︁ amplitude τn below the maximum stress amplitude τam. Qualitatively the maximum of the cyclic hardening curve follows from the superposition of cyclic hardening of the matrix volume and of volume growth of the „soft”︁ PSB phase between the nucleation cycle number Nn and the saturation cycle number Ns.