Nanocomposites and nanomaterials

Formation of nanoscale phases during rapid solidification of Al-Cu-Si alloys
I. Shtablavyi1, N. Popilovskyi1, Yu. Kulyk1, R. Serkiz2, B. Tsizh3,4, S. Mudry1
1 Metal Physics Department, Ivan Franko National University of Lviv, Kyrylo i Mephodiy 8, 79005 Lviv, Ukraine
E-mail: nazar.popilovskii@lnu.edu.ua
2Solid State Physics Department, Ivan Franko National University of Lviv, 79005 Lviv, Ukraine
3 Kazimierz Wielki University in Bydgoszcz, 30 Chodkiewicza, Bydgoszcz, 85-064, Poland
4 Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv, 50 Pekarska, Lviv, 79010, Ukraine 

Ternary Al-Cu-Si system is the basis of wide range of lightweight high entropy alloys with unique properties. Their physical and chemical properties depend not only on the chemical composition of alloys but also on the morphology and distribution of phases. It is known that in the process of synthesis of high-entropy alloys, the ultimate goal is to obtain a material, consisting mainly of solid solutions of components. However, the presence of nanocrystalline phases in such alloys creates new opportunities to improve their mechanical properties. In this regard, the study of nanocrystallization processes in the formation of multicomponent alloys is an urgent task.
In this work, the formation of nanocrystalline phases in alloys of Al-Cu-Si system of near equiatomic composition is investigated. Alloys were obtained by crystallization from the liquid phase with different cooling rates. The phase composition of alloys was studied by X-ray diffraction method, and the microstructure as well as phase size were studied by electron microscopy. In order to study the crystallization process itself, the structure of these alloys was also studied in the liquid state.