Glass formation and crystallization of CU47Ti33Zr11Ni8X1 (X = Fe, Si, Sn, Pb) alloys

A group Of Cu47Ti33Zr11Ni8X1 (X = Fe, Si, Sn, Pb, numbers indicate at.%) bulk glassy alloys was produced by copper mold casting. The glass-forming ability (GFA) and the devitrification behavior were investigated by differential scanning calorimetry and synchrotron experiments. The GFA was evaluated by considering different parameters: the reduced glass transition temperature T-rg = T-g/T-1 (T-1 = liquidus temperature), the supercooled liquid region DeltaT(x) = T-x - T-g and a new parameter gamma defined as T-x/(T-g + T-1). DeltaT(x) has a maximum value of 57K for Cu47Ti33Zr11Ni8Si1. T-rg and gamma reach the highest values for the Cu47Ti33Zr11Ni8Fe1 and Cu47Ti33Zr11Ni8Si1 alloys. The comparison of the parameters indicates that T, and gamma correlate better with GFA than AT,. In situ recorded XRD scans reveal that the first crystallizing phase has a gamma-CuTi-type structure. The microstructure stable before melting contains a mixture of gamma-CuTi, Cu51Zr14, Cu2TiZr and Ti2Cu compounds. (C) 2004 Elsevier B.V. All rights reserved.