TiNiCuZrNbTa refractory high entropy alloy coatings fabricated using laser cladding: Microstructure and tribological behavior

Aerospace copper alloy components typically require high wear resistance at surface connections to withstand substantial mechanical loads. In this study, a new refractory high-entropy alloy Ti₃₅Ni₃₄Cu₁₀Zr₁₀Nb₈Ta₃ coating was fabricated on copper substrate via laser cladding and its microstructral characteristics and tribological behaviors were fully explored to enhance surface durability. The results show that the obtained coatings exhibit a dense, defect-free microstructure with strong interfacial bonding, composed predominantly of TiNb, TiCuNi, and Zr₁₄Cu₅₁ phases. These features contributed to a significant improvement in wear resistance compared to conventional high entropy alloy. It is recognised that the presence of TiO₂, ZrO₂, Nb₂O₅, and Ta₂O₅ in the composite structure promoted the formation of a stable oxide layer during wear. The synergistic deformation behavior of these metal oxides helped reduce strain localization, thereby enhancing the coating’s durability. The research outcomes establish a viable strategy for tailoring the surface architecture of copper-based components, offering a pathway toward extended operational lifespans in harsh environments.