Laser deposition of high-entropy alloys: A comprehensive review

•LDMs applied for HEA materials along with laser processing parameters influencing the properties of the depositions are illustrated.•Various mechanical and functional properties of the laser-deposited HEA coatings are summarized.•Possible challenges and future trends of the laser-deposited coatings of HEAs are provided. 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 microstructural 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.