Deformation behavior of Zr-based bulk nanocrystalline amorphous alloys

Mechanical properties of bulk Zr₅₅Ni₅Cu₃₀Al₁₀ metallic glass alloy and Zr₅₃Ti₅Ni₁₀Cu₂₀Al₁₂ nanocrystalline-amorphous alloy were measured by compression tests at room temperature. Although no distinct plastic deformation is recognized in the Zr₅₅Ni₅Cu₃₀Al₁₀ metallic glass, the Zr₅₃Ti₅Ni₁₀Cu₂₀Al₁₂ as-quenched alloy exhibits significant plastic strain. Moreover, we found that both the strength and plastic strain increased significantly with increasing volume fraction of nanocrystals, and the plastic strain achieved a maximum in the early stage of nanocrystallization. High-resolution electron microscopy showed that nanocrystals with average grain sizes of about 2.0 and 2.5 nm were embedded in the amorphous matrix of the as-quenched bulk Zr₅₃Ti₅Ni₁₀Cu₂₀Al₁₂ alloy and the specimen with the maximum plastic strain, respectively.