Soudage de deux métaux dissimilaires (Al/Cu).

Abstract

This doctoral thesis was carried out as part of a WBI scientific collaboration project between the University of Biskra directed by Pr. Zakaria BOUMERZOUG and the University of Mons in Belgium directed by Pr. Fabienne DELAUNOIS. The aim of this investigation is to study the effect of time and temperature on the solid state diffusion welding of commercial aluminum alloy 2xxx series with a pure copper at 450°C, 475 °C, 500°C, and 525°C during holding times from 15 min to 240 min and to propose optimal welding temperature and holding time that permit to obtain a sound joint (defects-free and exhibiting a minimum IMCs). The main characterization techniques were optical microscopy, scanning electron microscopy, energy dispersive spectrometry, nanoindentation, microhardness measurements, and X-ray diffraction. Results showed that increasing the temperature and the holding time had an effect on the apparition of the intermetallics at the Al alloy/Cu interface. Five intermetallic phases namely Al2Cu, AlCu, Al3Cu4, Al2Cu3 and Al4Cu9 were identified at the interface. The micromechanical properties of the welded joint Al/Cu alloy varied also with the time and temperature. The nanoindentation measurements showed that the highest values of hardness were recorded in AlCu and Al3Cu4 phases. The optimal welding parameters that permitted to obtain a sound joint were: T=500°C and t=15min.