Metallic glass nanowires were spontaneously created on the fracture surfaces that were produced by a conventional mechanical test. The presence of the nanowires is directly related to the one-dimensional meniscus configuration with a small viscosity at high temperatures and to the wide supercooled liquid region of the metallic glass. The electron microscopic observations demonstrate the diameters, the lengths, and the amorphous structural states, and the energy dispersive X-ray reveals the chemical components. In addition, we found that round ridges are constructed from nanotubes. The finding of amorphous nanostructures not only provides a fundamental understanding of fracture processes but also gives a new insight into nanoengineering constructions.

Bulk glassy alloy rods with a diameter of 16 mm and a length of 40 to 45 mm were produced for Zr 65 Al 7:5 Ni 10 Cu 17:5 alloy by a tilt casting method. The alloy specimens taken from the different sites which are away by about 10 mm, 15 mm and 30 mm from the bottom surface of the cast rod consist of a glassy phase and their thermal stability, mechanical properties and fracture mode are almost independent of the specimen sites. The glass transition temperature, temperature interval of supercooled liquid region before crystallization and heat of crystallization are about 643 K, 102 K and 55 J/g, respectively, for the specimens taken from the three different sites. Besides, Young's modulus, yield strength, fracture strength, yield strain and plastic strain of the specimens are about 87 GPa, 1540 MPa, 1580 MPa, 0.018 and 0.005, respectively. The fracture mode consisting of shear plastic deformation along the maximum shear stress plane, followed by an instantaneous final rupture is also independent of the specimen sites. These data indicate that the cast glassy alloy rod with a diameter of 16 mm has nearly the same characteristics, though the cooling rate is significantly dependent on sample sites. The knowledge of producing the Zr-based bulk glassy alloy rod with nearly the same characteristics in the large diameter range up to 16 mm is encouraging for future applications of bulk glassy alloys as a new type of engineering material.

Bulk glassy alloy rods with a diameter of 20 mm were produced for Zr 61 Ti 2 Nb 2 Al 7:5 Ni 10 Cu 17:5 and Zr 60 Ti 2 Nb 2 Al 7:5 Ni 10 Cu 18:5 by a tilt casting method. The replacement of Zr by a small amount of Ti and Nb caused a distinct increase in the maximum diameter from 16 mm for Zr 65 Al 7:5 Ni 10 Cu 17:5 to 20 mm, accompanying the decrease in liquidus temperature and the increase in reduced glass transition temperature. The primary precipitation phase from supercooled liquid also shows a distinct change, i.e., from coexistent Zr 2 Cu, Zr 2 Ni and Zr 6 NiAl 2 phases for the 65%Zr alloy to an icosahedral phase for the 61%Zr and 60%Zr alloys. These results allow us to presume that the enhancement of the glassforming ability is due to an increase in the stability of supercooled liquid against crystallization caused by the development of icosahedral shortrange ordered atomic configurations. The 60%Zr specimens taken from the central and near-surface regions in the transverse cross section at the site which is 15 mm away from the bottom surface of the cast glassy rod with a diameter of 20 mm exhibit good mechanical properties under a compressive deformation mode, i.e., Young's modulus of 81 GPa, large elastic strain of 0.02, high yield strength of 1610 MPa and distinct plastic strain of 0.012. Besides, a number of shear bands are observed along the maximum shear stress plane on the peripheral surface near the final fracture site. The finding of producing the large scale Zr-based bulk glassy alloys exhibiting reliable mechanical properties is encouraging for future advancement of bulk glassy alloys as a new type of functional material.