New nano-lamellar eutectic high-entropy alloy coating by laser cladding

A novel Al27Cr25Ti18Nb18Zr12 eutectic high entropy alloy (EHEA) coating with BCC/B2 and Laves phase has been developed by laser cladding on Ti-6Al-4V alloys. The average microhardness of EHEA coating was ∼697.6HV0.3, which significantly surpasses the values reported for most eutectic high-entropy alloy coatings. The strengthening effect and additional strain hardening sources generated by the intersecting nanometer-spaced stacking faults and Lomer-Cotrell locks which found in BCC/B2 phase are important reasons for the superior hardness. And the adhesive problem of Ti-6Al-4V alloy was ameliorated by the EHEA coating with lower friction coefficient (83.05% of the Ti-6Al-4V alloy) and volumetric loss (27.75% of the Ti-6Al-4V alloy).