Effects of Ni, Ti and Hf on the glass forming ability of the Ni-Ti-Hf ternary alloys

Under the framework of the second-moment approximation of tight-binding model, a relevant potential with a binomail-truncated function proposed by the present authors is developed for Ni-Ti-Hf ternary system. Based on the newly constructed Ni-Ti-Hf potential, molecular dynamics (MD) simulations upon solid solution models predict that the glass forming ranges of Ni-Ti and Ni-Hf systems are 32-87 at.% of Ti and 20-85 at.% of Hf, respectively, and that Ti and Hf cannot form amorphous alloys in whole composition. Importantly, the predicted results are in a good agreement with the results derived from other theoretical methods and the experimental observations. Meanwhile, the effects of Ni, Ti, and Hf, respectively, on the glass forming ability (GFA) of the Ni-Ti-Hf alloys also have been predicted by MD simulations based on the constructed Ni-Ti-Hf ternary potential. The simulated results reveal that Ni and Hf can improve the GFA of Hf(Ti)-based and Ni-based Ni-Ti-Hf ternary alloys, respectively, while Ti will reduce the GFA of Ni-based Ni-Ti-Hf alloys, which also match well with the experimental observations and are in accordance with some proposed empirical models. (c) 2007 Elsevier B.V. All rights reserved.