Recherche d'un modele pour l'evolution de la limite elastique d'un alliage AlCu 4% a l'etat θ′

Abstract

This article examines the evolution of the elastic limit of an aluminium alloy with 4 weight per cent copper, in the θ′ state. Various treatments allow the distribution and the geometrical characteristics of the precipitates to be changed. Among the proposed models, of “cellular” or “Lamellar” types, we show that only a lamellar model accounts for elastic limit changes in every studied state. In this model we have to consider clusters of θ′-precipitates of the same family, with an average interval h ̄ . To describe the change R E in elastic limit associated with precipitation, we establish the relation ΔR E = ΔR E 0 + α h ̄ −1 2 . The precipitates spacing seems to determine alone the change in elastic limit, even if clusters have a very small extent and contain only a few precipitates.