A path-dependent constitutive model for gilding copper

Abstract
A constitutive model for gilding copper is presented. The model is an extension of a successful pathdependent model developed by Goldthorpe for the deformation of fcc materials. Gilding copper is a face-centred cubic metal and its deformation behaviour is, therefore, fully dependent upon the load path taken. This pathdependent model is the first constitutive model that treats path-dependency in a physically realistic manner and gives a complete description of loading and unloading paths; it can be implemented into hydrocodes with no significant cost. The necessity for extending the model using gilding copper as an exemplar material is to include the effects of alloying and of prior processing into the model. It introduces a generic principle in which the underlying dislocation dynamics are governed by the copper. All aspects of the model are presented and explained and determination of the constants for the model from experimental data is shown. Validation of the model by comparison with mechanical tests performed under changing conditions is presented together with predictions for the same tests using the Armstrong-Zerilli model.