CoCrMoNbTi refractory high-entropy alloys prepared by mechanical alloying combined with laser cladding

CoCrMoNbTi refractory high-entropy alloy powders were prepared by mechanical alloying, and the CoCrMoNbTi high-entropy alloy coatings were successfully prepared by laser cladding technology. The influence of ball milling time on the phase composition and microstructure of the CoCrMoNbTi refractory high-entropy alloy powders and coatings were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrum (EDS) analysis. The results show that, with the increase of milling time, the diffraction peak of the pure metal phase gradually disappears, which is mainly related to the melting point of the alloying element. In addition, the powder morphology changes significantly with the extension of milling time. The powders are extruded from the original state into the flake, and the flake powders are gradually welded together to form the flat powder particles. When the milling time reaches 40 h, the powders are completely alloyed, the powder shape tends to be spherical and greatly refined, and the elements in the powders are evenly distributed, forming a stable single-phase body-centered cubic solid solution structure. The CoCrMoNbTi refractory high entropy alloy coatings prepared by laser cladding technology have the good forming quality. The coatings are mainly composed of the body-centered cubic solid solution structure and a small amount of Cr₂Nb and Co₂Ti compounds, forming a fine and compact dendritic structure.