INTERACTIONS BETWEEN DISLOCATIONS AND CRYSTALLINE DEFECTS DURING THE CYCLIC DEFORMATION OF A 0.7 Wt% Al-Li ALLOY

Abstract
In the aerospace industry requirements for new materials with high mechanical properties and low density has stimulated research works in Al-Li alloys. For ten years numerous studies have been developed in order to promote complex alloys having convenient mechanical and physical properties, and able to replace conventional alloys /1/ and /2/. From a fundamental point of view basic researchs to study the microscopic mechanisms controlling the mechanical behauiour of Al-Li alloys have to entered upon because several microscopic mechanisms are not well understood. Such investigations were first conducted on binary Al-Li alloy in solid solution state or having a fine distribution of δ' (Al₃Li) precipitates, according to the amount of lithium atoms. Tensile properties /3/ or cyclic behaviour /4/, /5/ have been investigated. The ain of this paper is to determine in terms of dislocation-crystalline defect interactions the microscopic mechanisms involved in the cyclic deformation of a solid solution of a binary Al-Li alloy, containing 0.7 Wt % of lithium. This work is a part of a whole research program devoted to Al-Li binary alloys in our laboratory and therefore is complementary to studies presented in reference /5/.