INFLUENCE OF COOLING RATE AND ALLOYING ELEMENTS ON THE MICROSTRUCTURE OF THE Al-Mn-BASED ALLOY
Aluminum-based alloys have been used extensively for the past five decades primarily due to their good strength vs. specific weight ratio. Numerous methods and techniques have been devised to further improve mechanical properties of these alloys as they are often used in the transport applications. Influence of the cooling rate and chemical composition on the constitution of Al-Mn-based alloy has been investigated. Elements such as B, Be, C, Ca, Cu, Fe, Mg, Si, Sr and Ti have been introduced to Al-Mn alloys in order to study their influence. Changes in cooling rates during casting using permanent copper molds with different sized troughs have also been monitored. Combined influence of changes in chemical composition and cooling rates was followed using LOM, SEM, EDS, DAS measurement and mathematic modeling. It has been established that Al-Mn-based alloys form a lot of different phases during synthesis and solidification, mostly crystalline intermetallics, but also in some cases quasicrystalline (QC) ones, especially when cooling rates exceed 500 Ks-1. QCs are currently also considered as an alternative for reinforcement of Al-Mn-based alloys. It was found that in the case of alloy system Al-Mn-Cu-Be and cooling rates between 500 and 1350 Ks-1 the preferred phase formed was an icosahedral QC phase or iQC. Icosahedral QC phase formed as the primary phase and in some cases also in the form of the quasicrystalline eutectic (αAl + iQC). Additions of B, C, Ca, Ti and Sr have not proven to be effective in promoting formation of quasicrystals in cast Al-Mn alloys whilst Fe, Cu, Mg and Si proved to be highly efficient.
 K. F. Kelton, Quasicrystals: structure and properties, International Materials Review, Vol. 38−3 (1993) 105−137.
 A. Inoue, H. Kimura, Fabrication and mechanical properties of bulk amorphous, nanocrystalline, nanoquasicrystalline alloys in aluminum based system, Journal of Light Metals 1 (2001) 31–41.
 F. Schurack, J. Eckert, L. Schultz, Synthesis and mechanical properties of cast quasicrystal-reinforced Al-alloys, Acta mater., Vol. 49 (2001) 1351–1361.
 B. Markoli, T. Bončina, F. Zupanič, Behaviour of a quasicrystalline strengthened Al-alloy during compression testing = Verhalten einer quasikristallinen Aluminiumlegierung im Druckversuch, Mater. wiss. Werkst. tech., Vol. 43−4 (2012) 340−344.
 F. Zupanič, T. Bončina, N. Rozman, B. Markoli, Quasicrystal-strengthened cast Al-alloys, RMZ − mater. geoenviron, Vol. 58−1 (2011) 1−14.
 S. V. Divinski, On the possible types of quasicrystal structures, Scripta mater., Vol. 34 (1996) 1351–1355.