Abstrakt
This paper comprises a survey of the microstructure, phase composition, physical properties and processing of Al-Mn based aluminum alloys used for the production of automotive heat exchangers. After twin-roll casting the aluminum foil undergoes during fabrication several annealing and cold-rolling steps.
All these steps have influence on properties of the final product. During the thermomechanical treatment precipitation of dispersoids and coarsening of primary phases occur.
Dominant phases are -Al15(Fe,Mn)3Si2 and Al6(Fe,Mn). Deformed grains are replaced by new ones during recrystallization which results in softening of the material.
Enhanced properties can be achieved by adding minor alloying elements like zirconium or chromium. Zirconium can form fine precipitates which retard recrystallization and stabilize microstructure but their inhomogeneous distribution can decrease this favourable effect.