Deformation behavior of Zr-based bulk nanocrystalline amorphous alloys

Mechanical properties of bulk ${\mathrm{Zr}}_{55}{\mathrm{Ni}}_5{\mathrm{Cu}}_{30}{\mathrm{Al}}_{10}$ metallic glass alloy and ${\mathrm{Zr}}_{53}{\mathrm{Ti}}_5{\mathrm{Ni}}_{10}{\mathrm{Cu}}_{20}{\mathrm{Al}}_{12}$ nanocrystalline-amorphous alloy were measured by compression tests at room temperature. Although no distinct plastic deformation is recognized in the ${\mathrm{Zr}}_{55}{\mathrm{Ni}}_5{\mathrm{Cu}}_{30}{\mathrm{Al}}_{10}$ metallic glass, the ${\mathrm{Zr}}_{53}{\mathrm{Ti}}_5{\mathrm{Ni}}_{10}{\mathrm{Cu}}_{20}{\mathrm{Al}}_{12}$ 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 ${\mathrm{Zr}}_{53}{\mathrm{Ti}}_5{\mathrm{Ni}}_{10}{\mathrm{Cu}}_{20}{\mathrm{Al}}_{12}$ alloy and the specimen with the maximum plastic strain, respectively.