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J Kirschner, C. Eisenmenger-Sittner, G. Rasinger, R. Gaschl, J. Bernardi, A. Großalber, S. Frank, C. Simson:
"Stoichometry-driven Crystallographic Phase Transitions of AlCuMgZn Alloys";
Vortrag: THERMEC 2021, Wien; 01.06.2021 - 05.06.2021.

The development of novel light metal alloys represents an important task in the further optimization of technical materials. Multi-component systems with more than 4 metals are very promising to outperform the currently existing alloys, but lack significant research in systems not dominated by transition metals to date.
Thus a detailed structural investigation of the crystallography is essential for predicting the properties of multi-component systems. In this work we synthesized layers of Al, Cu, Mg and Zn, which are promising components for novel light-metal alloys.
Multi-component layers were co-deposited by magnetron sputtering. Different geometric arrangements of the sputter sources to each other and the use of various sputter targets resulted in the generation of a composition gradient on the substrate. Starting from pure Al, Cu, Mg and Zn, the stoichiometry was adjusted towards a more uniform distribution of the elements. The variation of the relative quantity of the constituents can lead to the formation of new phases. Since sputter deposition is a non-equilibrium process, the formation of crystallographic orders could be investigated by subsequent heat treatment and microstructural comparison to `as-deposited´ samples.
Grazing-incidence XRD measurements showed a composition-dependent continuous change of different crystal structures with combined phases of all constituent materials including hexagonal and cubic systems. In addition, hardness and morphology showed a non-trivial dependence on composition and crystallography. These results help answering the question, which metals are the driving elements for the formation of certain crystalline systems and how a simple structure without brittle intermetallic phases can be accomplished.

Keywords: Magnetron-Sputtering, Multi-Principal Element Alloys, Crystallography, Light Metal Alloys