Microstructure and corrosion properties of Al2CrFeCo x CuNiTi high entropy alloys prepared by additive manufacturing

Highlights: • Al₂CrFeCo_xCuNiTi high entropy coatings were prepared by additive manufacturing. • The coating is mainly composed of equiaxed grains and columnar grains. • By addition 2% Si and adjusting processing parameters, cracks are eliminated. • The corrosion resistance of the coatings is excellent. -- Abstract: The Al₂CrFeCo_xCuNiTi high-entropy alloy coatings were prepared by additive manufacturing. The microstructure and corrosion resistance were researched. The results show that the microstructure of Al₂CrFeCo_xCuNiTi high entropy alloy coating is mainly composed of equiaxed grains and columnar grains, with fine spherical particles distributed on the equiaxed grains. The coating is easy to crack under the action of thermal stress. The internal stress can be reduced and the crack can be eliminated by adding 2% Si and additive manufacturing process. The corrosion resistance of the coating with 2% Si addition in 0.5 mol/L HNO₃ solution is excellent, compared with Q235 steel, the self corrosion current density of the coating is reduced by 1–2 orders of magnitude, and the self corrosion potential shifted to the positive direction by 0.02–0.30 V. The corrosion resistance of the coating decreases with the increase of Co content.