Effect of Thermomechical Pretreatment on Mechanical Properties of Modified Al-Mn-Fe-Si Based Alloys
Fins in automotive heat exchangers are manufactured from Al-Mn-Fe-Si foils. Since continuous twin-roll casting (TRC) reduces energy and work consumption, it is the preferred manufacturing technology. The precipitation processes resulting from annealing of TRC Al-Mn-Fe- Si based alloys were studied by resistometric measurements during linear heating from room temperature up to 620 °C, hardness measurements and transmission electron microscopy examinations. Primary particles and precipitates of the cubic α-Al15(Mn,Fe)3Si2, hexagonal Al8Fe2Si and orthorhombic Al6(Fe,Mn) phases were identified. Phases of different types prevail in different alloys depending on composition. The increase of cold rolling prestrain prior to annealing induces a significant shift to lower temperatures of the start of precipitation. Prestrain accelerates precipitation kinetics by redistributing solute atoms and favoring their segregation on nucleation sites such as dislocations, subgrain and grain boundaries.
M. Cieslar et al., "Effect of Thermomechical Pretreatment on Mechanical Properties of Modified Al-Mn-Fe-Si Based Alloys", Materials Science Forum, Vols. 567-568, pp. 325-328, 2008