Novel laser rapidly solidified medium-entropy high speed steel coatings with enhanced hot wear resistance

The microstructure and hot wear resistance of a laser cladded novel medium-entropy high speed steel (ME-HSS) coating, by increasing the content of alloying elements Mo, V, Co, Ni and Al in a commercialized W6Mo5Cr4V2 (M2) HSS, are studied here. The results show that the newly designed ME-HSS coating has less amount of undesired retained austenite, and enhanced secondary hardening effect with more nano-size M2C carbide precipitates after tempering, in comparison with the M2 coating. In particular, the tempered ME-HSS coating exhibits excellent oxidative wear resistance at 500 °C because of the high content of anti-oxidation elements like Co, Ni and Al, leading to the formation of a more continuous and compact oxidation film on its worn surface.