Micro and nanosized materials with high entropy

Abstract

The stability of high-entropy alloys, like equiatomic and non-equiatomic micro- and nanostructural ones, is relevant when creating stable multicomponent compositions with improved performance. The implementation of such materials is possible by mechanical alloying, magnetron sputtering, as well as by the electrochemical method using the «top-down and bottom-to-top» strategy at moderate temperatures < 200°C with controlled production of both micro-from 0,5 to 20 μm and nanoscale high-entropy alloys with particles from 2 to 10 nm. The well-studied «structure-property» relationship for classical alloys is not yet completely clear for nano-high-entropy alloys, but it is obvious that it is possible to form excellent mechanical characteristics by selecting chemical compositions and a special heat treatment regime. Regarding the chemical composition, requirements are imposed both on the main components and alloying additives. Preliminarily, not only compositions are selected, but also methods for the synthesis of high-entropy alloys, including ab initio (density functional theory), neural network prediction, and classical molecular dynamic simulation with possible conditions for the formation of model nano- high-entropy alloy samples, as well as derivative options. The resulting descriptions are compared with real methods of high-entropy alloys synthesis, for example, exposure to various synthetic media.

Keywords

• multicomponent
• amorphous and nanocrystalline alloys
• high-entropy alloys
• nano- high-entropy alloys
• strain hardening
• landscape-local fluctuations
• strength
• thermal stability
• layered composites
• thermodynamic calculations