Author: KS Evangelista, DGL Cavalcante Institute: Technological Center of the Federal University of Paraiba, João Pessoa, Paraiba, Brazil
X-ray diffraction (XRD) is a powerful tool for studying quasi-crystalline phases in high-energy milled powders such as Al/AlCuFe. Quasicrystals, possessing a unique order of matter in three-dimensional space, exhibit anomalous physical properties, making them an object of active research for application in modern materials with unique characteristics.
In the course of experimental studies using the X-ray diffraction method, we can identify structural changes in the quasi-crystalline phase at different temperatures and mechanical effects, which is key to understanding their thermodynamic stability. The use of high-energy milling in the process of synthesis of Al/AlCuFe powders affects the formation and preservation of the quasi-crystalline structure, changing the kinetic barriers for phase formation.
Analysis of the obtained data allows us to establish the relationship between microstructural changes and the physical and chemical properties of the material. Identification of stable and metastable states of the quasi-crystalline phase opens up new horizons for the use of such materials in the field of high-tech composites and additive manufacturing.
Quasi-crystalline alloys have been studied for over three decades due to their unique structure, which provides special mechanical and surface properties, such as high strength and low friction coefficient. The AlCuFe alloy, due to its low cost, safety and availability of components, has been the subject of intensive study. Potential applications of this alloy include its use as a reinforcement material in metal composites, particularly with aluminum, where the quasi-crystalline phase improves the strength compared to pure aluminum.
To obtain such composites, uniaxial hot pressing and spark plasma sintering methods were used. Before the process, it was necessary to mix aluminum powders with quasi-crystalline ones, which was usually done by high-energy grinding. However, in some cases, the transformation of the quasi-crystalline phase into approximants is observed, which negatively affects the characteristics of the composite. For this purpose, this study is aimed at studying the stability of the quasi-crystalline phase in the Al/AlCuFe alloy after mechanical mixing.
Al62.5Cu25Fe12.5 alloys were obtained by melting in an induction furnace under argon. Heat treatment of the samples was carried out to improve the composition and increase the proportion of the icosahedral phase. Quasicrystal powders were obtained by mechanical processing and sieving. High-energy milling was carried out in a planetary ball mill, which minimized phase transformations. X-ray diffraction was used to characterize the powders, and phase identification was carried out according to the JCPDS database.