Glass formation in a high entropy alloy system by design

The alloys (TiZrNbCu)(1-x)Ni-x x = 0.125, 0.15, 0.2, 0.25 were produced by vacuum arc melting and investigated as a potential high entropy alloy and glass forming system. The alloys x = 0.125 and 0.15 were capable of forming either amorphous or high entropy alloy phases, increasing the Ni content destabilised the high entropy alloy phase. This behaviour is explained by considering the enthalpy and entropy of mixing of the alloys and decomposition products. The unique feature of the high entropy alloys in this study was the high vacancy formation energies compared to other reported high entropy alloys and this is believed to be responsible for their ability to form an amorphous phase and their relative sensitivity to Ni content. (C) 2011 Elsevier Ltd. All rights reserved.