THE INFLUENCE OF THERMAL AND SURFACE TREATMENTS ON THE ANELASTIC CREEP OF AL-ZN AND AL-CU ALLOYS

In many industrial applications, like high precision force measurement s or nanopositioning, the elastic and dimensional stabilities of mater ials are required at a nanometric scale. Therefore, some aspects of ro om temperature creep of commercial Al-Zn and Al-Cu alloys have been st udied. The anelastic creep was measured at room temperature by means o f a high resolution laser interferometer. The irreversible component o f the deformation was quantified by measuring the viscoelastic after-e ffect. The anelastic relaxation of Al-Zn has been studied as a functio n of annealing time and temperature. The results are correlated with t he size and the density of precipitates and the extension of the preci pitate free zone. The influence of a surface treatment (sandblasting, electropolishing, Cu-galvanizing, chroming, Zn-plating) on anelastic r elaxation has also been considered and explained in terms of the anela stic and elastic properties of both the surface layer and the bulk.