Compositive role of TiB₂ in microstructure optimization and wear-resistant improvement of selective-laser-melted TiB2_p/CrCoFeNiMn high-entropy composite

The CoCrFeNiMn high-entropy alloy and TiB2_p/CoCrFeNiMn high-entropy composite (HEC) were manufactured by Selective laser melting. For the CoCrFeNiMn, a coarse epitaxial columnar microstructure with strong crystallographic textures was generated. While in the TiB2_p/CoCrFeNiMn, TiB₂ particles are distributed in the significantly refined dendrites and nearly equiaxial grains, and phase transformation occurs to form σ phase. TiB₂ and σ phase construct a strong interface relationship with the matrix. TiB2_p/CoCrFeNiMn HEC has extremely high microhardness (329 ± 2 HV) and excellent wear resistance (coefficients of friction 0.31 ± 0.02). The wear mechanism of the HEC was studied refer to the microstructure, composition and hardness. IMPACT STATEMENT TiB₂-reinforced CoCrFeNiMn-based high-entropy composite is successfully fabricated by Selective laser melting, which exhibits exceptional hardness and the best wear resistance.