Thermokinetic analysis of intermetallic growth in copper clad aluminium wires
Résumé
To increase the ductility of bimetallic wires after deep drawing process, annealing is generally performed, leading to the diffusion between both metals. This paper focuses on the microstructural and thermokinetic properties of copper clad aluminium wires in order to optimise their process and properties. Solid state diffusion reaction was carried out in the temperature range of 573–673 K and time range of 2–48 h. Intermetallic microstructures were analysed thanks to focused ion beam, electron backscattered diffraction and energy dispersive spectroscopy techniques and compared to previous results obtained by friction welding process. Al2Cu, AlCu and Al4Cu9 phases were formed near the Cu/Al interface after heat treatment. The growth kinetic of these intermetallics can be followed by volume diffusion process. To predict the formation of first intermetallic phase, the effective heat of formation model was used and predicts the growth of Al2Cu and AlCu as first compounds.