Exchange Mediated Interaction of Dislocations and Deformation Hardening of Invar Alloys

Abstract

We propose an explanation of anomalies observed in the behavior of deformation hardening of Invars. An extremely strong volume magnetostriction, typical of Invars, results in an enhancement of the exchange contribution to the energy of the dislocation system by about three orders of magnitude with respect to its value in conventional ferromagnetics. Both the self energy of individual dislocations and the interaction between them, determined usually only by the elastic deformation, in Invars is strongly diminished by the contribution of the exchange energy. This fact explains a strong suppression of the deformation hardening rate in the second stage as well as its strong temperature and content dependence in Invars.