A Review on High Entropy Alloys Coatings: Fabrication Processes and Property Assessment

Abstract

Surface coatings can enhance the mechanical and functional properties of substrates and keep good balance between specific mechanical properties and sufficient surface performance of the components. Coatings composed of high entropy alloys (HEAs) and HEA‐based materials, including metallic, ceramics, and composites have attracted the global attention and developed rapidly over the last decade, owing to their outstanding properties. Here, the authors provide a critical review of the state‐of‐the‐art for HEA‐based coatings, aiming to address the related conceptions, designing principles, microstructural, and mechanical evolutions during fabrication and post‐treatments process. The surface properties which are not limited to anti‐corrosion, anti‐radiation, and anti‐diffusion and their underlying mechanisms are analyzed. The development tendency and future applications are classified and discussed, including the basic researches about HEAs, the regulations of fabrication techniques and the exploring of functional properties of HEA‐based coatings. Due to their superior mechanical and functional potentials as well as abundant element‐constitutions of designing, surface coatings composed of HEA‐based materials are considered to have promising applications in engineering and industrial manufacturing.

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

“…Similar as for steels and other applied alloys, the occurrence of hard and brittle Laves phase precipitates was regarded as detrimental for a long time, see, for example, [1078]. However, today HEAs are intensively discussed as wear-and oxidation-resistant coatings for structural materials [1102], and the high hardness and excellent wear resistance of Laves phase have been recognized as very beneficial to improve the properties of such coatings [550][551][552][553][554][555][556][557].…”

The (110) and (320) surfaces of a Cantor alloy

“…9 The use of HEA is also considered in the form of coating due to their excellent surface properties compared to conventional alloys including oxidation, corrosion and wear resistance. [10][11][12] The deposition conditions will vary with the selected growth techniques (chemical, physical...) and HEA systems. To achieve the growth of a single phase HEA coating, several parameters including annealing treatment, adsorption sequences should be fined tuned.…”

Tribological Properties of High-Entropy Alloys under Dry Conditions for a Wide Temperature Range—A Review

“…These three elements are also included in the highly studied Cantor alloy, CrMnFeCoNi [ 19 ]. This alloy and its five base elements are often used as a starting point for developing other HEAs by either replacing an element or adding small portions of an additional alloying element [ 9 ]. It is also important to highlight that out of the 40 different base HEAs in this review, 31 of them are either a Cantor alloy or a variation of it.…”

“…In the past five years, publications concerning HEAs have dramatically increased as the field of material science seeks to develop application-specific alloys. Additionally, books and literature reviews have been published in hopes of starting to collect and organize the rapidly growing body of literature from a broad spectrum of HEAs [ 5 , 6 , 7 , 8 , 9 ] according to the specific criterion or properties of HEAs, such as nanocrystalline [ 10 ], refractory [ 11 ] phase transition and corrosion properties [ 12 ], fatigue, fracture properties of HEAs [ 13 ], high-temperature wear [ 9 , 14 ], and additive manufacturing of HEAs [ 15 ]. Along with the influx of general development and characterization work for HEAs, there has also been an increase in tribological studies to understand the friction and wear performance of these alloys.…”