Strengthening behavior of AlCoCrFeNi(TiN) high-entropy alloy coatings fabricated by plasma spraying and laser remelting

Abstract

• In-situ TiN-Al 2 O 3 and cuboidal B2 phase combined strengthening HEA coatings • A square internally and round externally dual-phase nanoparticle structure formed. • Thermite reaction occurs during laser remelting. • The grains in AlCoCrFeNi HEA coatings were refined by additive TiN. High-entropy alloy (HEA) coatings are of great importance in the fabrication of wear resistance materials. HEA coatings containing ceramic particles as reinforcement phase usually have better wear performance. In this study, AlCoCrFeNi(TiN) x ( x : molar ratio; x =0, 0.2, 0.4, 0.6, 0.8, 1.0) HEA coatings were fabricated on Q235 steel by plasma spray first and then subjected to laser remelting. The experimental results confirm that plasma spray together with post laser remelting could result in the in-situ formation of TiN-Al 2 O 3 ceramic particles and cuboidal B2 phase in the AlCoCrFeNi(TiN) x HEA coatings. The in-situ TiN-Al 2 O 3 and nano-cuboidal B2 precipitation phase strengthened the coatings and improved their wear-resistance properties. Due to the dispersion of hard phase and nano-particles resulting from second heating, the microhardness of the AlCoCrFeNi(TiN) coatings significantly increased from 493 to 851 HV after laser remelting. For the same reasons, the wear-resistance performance was also significantly promoted after laser remelting.