Glass forming ability, thermal stability and elastic properties of Zr-Ti-Cu-Be-(Fe) bulk metallic glasses

Abstract

A series of Zr35−xTi30Cu7.5Be27.5Fex (x=0–10) bulk metallic glasses are cast using water-cooled copper mold casting technique. The glass forming ability (GFA) and thermal stability of Zr35−xTi30Cu7.5Be27.5Fex alloys were studied by means of X-ray diffraction and differential scanning calorimetry. It was found that the Zr35−xTi30Cu7.5Be27.5Fex (x=2, 3, 5 and 7, respectively) alloys could be cast into glassy cylindrical rods with a diameters up to 20mm. However, higher Fe content (x=10) deteriorates the GFA remarkably. The supercooled liquid region (ΔTx), γ parameter (defined as Tx/(Tg+Tl)) and the reduced glass transition temperature Trg (defined as Tg/Tl) are employed to evaluate the GFA in Zr35−xTi30Cu7.5Be27.5Fex (x=0–10) alloys. The results showed that Trg was more effective in gauging the GFA of the Zr35−xTi30Cu7.5Be27.5Fex alloy systems than ΔTx and γ parameter. In addition, elastic constant (Poisson’s ratio) was also employed as a gauge to evaluate the glass forming ability in Zr35−xTi30Cu7.5Be27.5Fex alloys.