L'influence de la déformation sur la recristallisation de l'alliage superplastique Al-Li.

Abstract

The superplastic behavior depends upon the structure of the material. Following appropriate thermo mechanical heat treatments a fine grain and stable microstructure can be obtained prior or during the early stages of superplastic deformation. The aim of the present work concerns the effect of deformation on the texture evolution of Al-Li alloy designed as (8090).In this study two deformation modes. uniaxial and compression have been used. They have a similar strain of 100%and the same temperature range between 300°C and 500°C.In order to study the initial structure of the material samples have been taken from the head of tensile specimens. To study the texture changes and the precipitation process, X rays have been used. The optical microscopy and scanning electron microscopy (SEM) have been used for simple observation. The results show that the recrystallization of the studied material is obtained during uniaxial testing mainly during the early stages of superplastic deformation. The recrystallization is also observed at a relatively high temperature.