The relations between ΔTx and the glass forming ability of bulk amorphous Zr-Cu-Ni-Al-Hf-Ti and Zr52.5Cu17.9Ni14.6Al10Ti5 alloys

The relative glass forming ability (GFA) of bulk amorphous Zr60Cu20NigAl7Hf3Ti2 (A(1)) and Zr52.5Cu17.9Ni14.6Al10Ti5 (Vit105) alloys has been investigated by comparing the maximum thickness of amorphous region of wedge-shaped samples, as well as the evaluated critical cooling rates using differential thermal analysis (DTA). The results show that the maximum thickness of amorphous region of wedge-shaped samples are d(m) = 2 mm for A(1), d(m) = 3.5 mm for Vit105, and the evaluated critical cooling rates are R-c = 33.5 and 4.5 K/s for A(1) and Vit105, respectively. It is suggested that the glass forming ability of A(1) is smaller than that of well known Vit105 alloy, though A(1) has the significant supercooled liquid region of over 140 K. Therefore, it is concluded that a large supercooled liquid region DeltaT(x) does not necessarily mean good glass forming ability of an amorphous alloy. (C) 2004 Elsevier B.V. All rights reserved.