Compositive Role of TiB2 in Microstructure Optimization and Wear-Resistant Improvement of Selective-Laser-melted TiB2p/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 sigma phase. TiB2 and sigma 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.