Comparative study of wet oxidation in amorphous and crystalline Zr-Cu-Al: The effect of structural order

The structural order significantly influences the oxidation resistance of alloys, but its effect on oxidation behaviors in humid environments remains underexplored. Herein, a comprehensive investigation of the effect of structural order on the wet oxidation of alloys was conducted using amorphous and crystalline Zr-Cu-Al alloys as model systems. The amorphous Zr-Cu-Al alloy exhibits stronger resistance to wet oxidation than its crystalline counterpart, which can be ascribed to the higher activation barriers associated with dense and disordered atomic structures of amorphous (Zr, Al)-oxide and substrate. An amorphous Cu-rich structure is observed in the amorphous alloy, whereas internal oxidation occurs in the crystalline alloy with a resulting multilayered Cu-rich structure (i.e. intermetallic compounds). This study highlights the critical role of structural order in oxidation resistance, providing new insights into the design strategies of alloys served in humid environments.