Design and preparation of gradient high-entropy alloy composite deposition layer by laser directed energy deposition

Balancing high hardness, strength, and toughness has long been a challenge for high-hardness deposition layers, limiting their thickness and applications. To solve this issue, this study innovatively designs a gradient high-entropy alloy (HEA) deposition layer by constructing a compositional gradient of Ti elements, successfully forming a material with gradient microstructure. This design facilitates a gradient variation in mechanical properties, significantly enhancing the overall performance of the material. The results demonstrated the successful development of a gradient HEA deposition layer with a thickness of 5.5 mm, exhibiting well-matched toughness. The hardness at the top, middle, and bottom of this layer was 528 HV, 361 HV, and 187 HV, respectively. This work offers a new approach to optimizing high-hardness deposition layers and advances the design of thick, wear-resistant materials.