Quantitative TEM study of the precipitation microstructure in aluminium alloy Al(MgSiCu) 6056 T6

François Delmas (1) , Marie-José Casanove (1) , Philippe Lours (2) , Alain Couret (1) , Armand Coujou (1)

1 CEMES - Centre d'élaboration de matériaux et d'études structurales
2 CROMeP - Centre de Recherche Outillages, Matériaux et Procédés

The precipitate microstructure in the last-generation aluminium alloy 6056 T6 [AlMgSiCu] is investigated using three complementary techniques of transmission electron microscopy (TEM) with a special focus on the density and volume fraction of strengthening particles. High-resolution TEM allows the identification of the precipitates and the measurement of the precipitate sizes to be performed. Conventional TEM is used to evaluate the number of precipitates in the investigated area as well as their distribution in the matrix. In situ TEM straining, via the analysis of the dislocation slip traces, permits to determine precisely the thickness and the volume of the foil in the region where the precipitates are analysed. Taking into account the shape and the dimensions of precipitates with respect to the foil thickness, a novel methodology for measuring the volume density and the volume fraction of precipitates is proposed.

Mots clés: Aluminium alloys; Precipitation hardening; Density and volume fraction; In situ straining experiments

Domaines: Sciences de l'ingénieur [physics]

François Delmas, Marie-José Casanove, Philippe Lours, Alain Couret, Armand Coujou. Quantitative TEM study of the precipitation microstructure in aluminium alloy Al(MgSiCu) 6056 T6. Materials Science and Engineering: A, 2004, 373 (1-2), pp.80-89. ⟨10.1016/j.msea.2003.12.068⟩. ⟨hal-01716116⟩