三元Cu-Zr-Ce合金的快速凝固组织调控与高温氧化机理研究

The metastable phase separation and amorphous formation capability of liquid Cu_57.6Zr_32.4Ce₁₀(at%) alloy under substantial undercooling and rapid cooling conditions were studied by drop tube and melt spinning techniques. The equilibrium solidification structure consisted of crystalline Cu₂Ce, Cu₁₀Zr₇, and Zr₂Cu phases. The alloy droplet diameters in containerless processing by drop tube ranged from 90 to 1066 μm. When the cooling rate was lower than 6.8 × 10³ K s⁻¹, the solidification microstructures of alloy droplets involved Cu₂Ce and CuZr phases. Once the cooling rate exceeded this threshold, the alloy melt underwent metastable phase separation, and its solidification microstructures contained spherical Cu₂Ce phase and Cu₅₆Zr₃₇Ce₇ amorphous phase. Under melt spinning conditions, the cooling rate increased from 8.7 × 10⁶ to 2.4 × 10⁷ K s⁻¹ with the increase of roller speed, and the size of Cu₂Ce phase formed by liquid phase separation decreased from 0.75 to 0.14 μm. When the cooling rate reaches 3.2 × 10⁷ K s⁻¹, the status of fully amorphous solidification was achieved. During high temperature oxidation, the presence of Cu₂Ce phase induced the formation of a Cu-rich oxide layer on alloy ribbon surface. This oxide layer acted as an effective barrier, preventing the inward diffusion of oxygen element and thereby facilitating the enhancement of oxidation resistance.