Ti-based bulk metallic glasses with high specific strength

Abstract

The glass forming ability of melt-spun Ti65-xZrxBe18Cu9Ni8 (x = 0, 5, 10, 15) amorphous alloys have been investigated by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). With increasing Zr contents, x from 0 to 15, DeltaTx (= T-x - T-g), T-rg (= T-g/T-l) and gamma (= T-x/T-g + T-l)), where T-g = glass transition temperature, T-x = crystallization temperature and T-l = liquidus temperature, gradually increase from 35 to 40 K, from 0.558 to 0.621, and from 0.378 to 0.406, respectively. The Ti65-xZrBe18Cu9Ni8 (x = 10, 15) BMG cylinders with the diameter up to 6 mm are successfully fabricated by the injection casting method, exhibiting high Vickers hardness (681-700) and yield strength (2.0-2.1 GPa). Ti-Zr-Be-Cu-Ni alloys with >50 at% Ti content have higher specific strength than any other Ti-based BMGs reported so far.