Phase transformations in the rapidly solidified Ti₄₀Zr₂₀Hf₂₀Pd₂₀ alloy

Abstract

We report that an approximant phase was initially obtained in amorphous Ti₄₀Zr₂₀Hf₂₀Pd₂₀ alloy. In the initial stage of the devitrification process, the approximant phase transforms into an icosahedral (I) phase with a high thermal stability while the cF96 Zr₂Ni-type (space group View the Fd3̅m with a = 1.25 nm and 96 atoms cell^-1) particles precipitate from the amorphous matrix. Eventually the I phase grows to several hundred nanometers when annealed at about 1000 K and then transforms into the Zr₂Ni-type phase with an endothermic reaction.