Secondary hardening in laser rapidly solidified Fe68(MoWCrVCoNiAlCu)32 medium-entropy high-speed steel coatings

Novel Fe68(MoWCrVCoNiAlCu)32 (at.%) medium-entropy high-speed steel (ME-HSS) coatings, containing various carbon contents from 0.65 to 1.05 wt%, are prepared by laser rapid solidification. The newly prepared ME-HSS coatings are characterized by a hard martensitic matrix enhanced by secondary hardening, and specifically by coherent nano-sized M2C. The secondary hardening effect is enhanced with the increasing carbon content. The high amount of alloying elements in ME-HSS coatings results in excellent oxidative wear resistance, without leading to serious compositional segregation and coarsening of carbides.