Effect of Ti addition on the crystallization behavior and glass-forming ability of Zr–Al–Cu alloys

The crystallization behavior of melt-spun (Zr65Al7.5Cu27.5)100−xTix (x = 0–15; in at.%) metallic glasses has been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The DSC traces showed an altered crystallization mode in the vicinity of 3 at.% Ti addition. A metastable icosahedral quasicrystal precipitated at the first crystallization stage of the Ti-bearing metallic glasses, which subsequently transformed to the stable Zr2Cu-type phase in the followed exothermic reaction. The glass-forming abilities (GFAs) of these metallic glasses were assessed by the recognized GFA indicators Trg, ΔTx and γ. BMGs were easily made in the compositions containing 3–7 at.% Ti by means of copper mold casting. The validity of these parameters was clarified using the critical BMG forming diameter evidence.