Influence of Si and Fe on the distribution of intermetallic compounds in twin-roll cast Al-Mn-Zr alloys

The aim of the experiments was to study the influence of Si and Fe on size and formation of secondary phases and recrystallization behavior of Al-Mn-Zr alloys prepared by twin-roll casting (TRC) in the industrial conditions. Microstructure (grain structure, phase composition, particle analysis) of these alloys was characterized during downstream processing. Quantitative particle analysis was carried out on FEG-SEM micrographs at both high and low magnifications. The phases were examined by light metallography, energy dispersive X-ray spectroscopy (EDXS) and by means of electron back-scattering diffraction (EBSD) according to their crystallographic structure. The microstructure at the final gauge was also observed by transmission electron microscope (TEM). A relatively high (0.5 wt.%) Si content and low (0.2 wt.%) Fe content in one of the alloys resulted in balancing of nucleation and dissolution rate for small particles. Hence a higher density of small particles was stable during the downstream processing, and this alloy showed improved recrystallization resistance. (C) 2011 Elsevier B. V. All rights reserved.