Significant plasticity and atomic-scale deformation mechanism of high glass-forming Zr-Cu-Ni-Ti-Al bulk glassy alloys

Abstract The authors report a series of monolithic Zr(65.4-x)Cu(12+x)Ni9.6Ti6Al7 (x = 0, 3, 6, 9 at.%) bulk glassy alloys with significant room-temperature plasticity and high glass-forming ability (GFA). Upon substitution of Cu for Zr, the GFA of glassy alloys is gradually increased, and the alloy possesses a critical casting size up to 10 mm when x=9. On the contrary, the plasticity is evidently increased with decreasing of Cu content in the glassy alloys, and the alloy exhibits the best plastic strain of 29.6% when x=0. Theoretical calculations indicate that the small differences in atomic sizes and atomic affinity among constituent elements should be necessary before pronounced plastic deformation can occur.