Zhang Baoqing

Improvement of Plasticity of Ti-Based Bulk Metallic Glasses by Addition of Nb

Ti-based bulk metallic glasses (Ti4oZr25Cu9Ni8Be18)100-xNbx with x = 0 to 5at.% are prepared by copper-mold casting. The glass formation ability is almost unchanged by addition of Nb. The compression plasticity is, however, apparently changed, from 3% at x = 0 to 13% at x = 3, about 330% increases at the strain rate of 1 × 10−4s−1. The increment of the plasticity can be attributed to the segregation of Nb in the area of shear bands during the compression processing. An effective way to increase the plasticity of Ti-based bulk metallic glasses is thus proposed.

Preparation and thermal stability of ZrCuAlMo bulk metallic glass

(Zr47Cu44Al9)100-xMox( x =0, 1, 2, 3) metallic glass alloys were prepared by copper mould casting. The effect of Mo addition on the glass-forming ability (GFA) and thermal stability was investigated by using X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The maximum diameter of glassy rods is increased from 4 mm for the base alloy to 6 mm for the (Zr47Cu44Al9)98Mo2 alloy without detectable crystallinity, and 8 mm sample owns very low diffraction peak. Due to suppression of the formation and growth of the primary CuZr phase, properly adding Mo enhances the GFA of the base alloy. The characteristic temperature apparent activation energy was calculated by the Kissinger equation. The activation energies of glass transition ( E g), crystallization ( E x) and peak crystallization ( E p) are 278.57 kJ mol?1, 392.46 kJ mol-1 and 376.97 kJ mol-1, respectively. Compared with the base alloy, 2% Mo addition can not only improve the glass forming ability, but also increase the thermal stability. The possible mechanisms were also discussed.