Illustration: High entropy material - ideal configuration - modelling vs measurement - real configuration
Source: BAM, Structure Analysis division
In the last decade, high-entropy alloys play an important role as a new class of multicomponent metallic materials. In contrast to classical alloys and steels with several micro editions of metallic or non-metallic components to one principle element such as iron to steels, high-entropy alloys contain five or more principle components with nearly equal concentrations. The complex composition of high-entropy alloys controls their structure and functional properties. Up to now, high-entropy materials were prepared for many metals to study their attractiveness for practical applications in energy storage and conversion, electrocatalysts and advanced nuclear applications.
One of the most promising examples for industrial applications is the five vein equiatomic single phase CrMnFeCoNi, which is the reason why intensive studies on such systems are growing. It not only delivers new knowledge about functional properties but also opens new fundamental questions which should be addressed before researchers and engineers can progress further in understanding nature.
It has been shown that the local composition of high-entropy alloys plays an important role in their macroscopic properties, such as mechanical and chemical stability as well as promising catalytic properties. To probe the local structure in the vicinity of each element (atom) requires the use of sophisticated X-ray methods found at large-scale facilities, called synchrotrons. With these, we probe local ordering and inner relaxations in complex multicomponent systems at the atomic scale in an element-specific way. Hence, opening a path to comprehensive structural studies of materials needed for modern technologies and applications.
In this multidisciplinary study, we apply synchrotron-based X-ray absorption spectroscopy as a powerful element-specific tool to characterize the local composition of CrMnFeCoNi high-entropy alloy. We probed each element separately to build a self-consistent picture of local structure on an atomic level.
Our interdisciplinary study demonstrates that all five components of the equiatomic CrMnFeCoNi alloy are distributed in the structure homogeneous and do not form any islands with predominant presence of one or two elements which has been postulated by previous studies. These findings promote high entropy materials with functional properties more applicable for a broader range of applications.
Inner relaxations in equiatomic single-phase high-entropy Cantoralloy
A. Smekhova, A. Kuzmin, K. Siemensmeyer, R. Abrudan, Uwe Reinholz, Ana Guilherme Buzanich, M. Schneider, G. Laplanche, Kirill V. Yusenko
published in Journal of Alloys and Compounds, Vol. 920, article 165999, page 1-31, 2022
BAM Structure Analysis division