The deviation from Matthiessen's rule and electrical dislocation density measurement in dilute Cu-Au alloys

The method of electrical dislocation density measurement, which was success ful in plastically deformed pure noble metals, is applied for the first tim e to dilute alloys, and the parameters for the electrical dislocation densi ty measurement, i.e. the temperature dependence of the deviation from Matth iessen's rule and of the low-field Hall coefficient were investigated in Cu -Au alloys with 0.075 and 0.3 at% gold. The results for the dislocation den sity. which rely on the modelling of the true dislocation resistivity by me ans of the two-group model are especially satisfactory for the 0.075 at% al loy. Additionally the dislocation density was checked by X-ray Bragg profil e analysis. The comparison of the latter method with the electrical method shows that small dislocation loops originating from the agglomeration of de formation induced vacancies are part of the total dislocation density.