Laser deposition of high-entropy alloys: A comprehensive review

Since the advent in 2004, high-entropy alloys (HEAs) have become an attraction for the world and applied in the extensive engineering fields due to their outstanding properties. These materials are exhibiting their potentiality for challenging conditions where coatings are applied through laser deposition technology. Laser deposition techniques containing laser cladding (LC), laser surface alloying (LSA), and laser surface remelting (LSR) are the modern technologies that can be applied for surface modification through HEAs. Nobler properties of the LC-HEA depositions over the conventional alloys have further explored this field in the last few years. Here, this paper provides a comprehensive state-of-the-art review for LC-HEA-based coatings, focusing on the use of laser deposition technique for HEAs, the effect of laser process parameters on mechanical properties, and micro structural evolution. The mechanical characteristics include but are not limited to hardness, wear, corrosion, and erosion resistance are discussed, with regard to their microstructure and phase composition. Besides, the existing problems, possible future developments regarding the LC-HEA depositions are predicted. Due to excellent mechanical properties and functional potential as well as a variety of element constitutions for HEA designing, laser assisted depositions containing blended HEAs as feedstock material will have promising applications prospects in the field of material science and engineering.