Production of quasicrystals and crystalline approximants in the Al–Pd–(Fe,Ru,Os) systems

We report the formation regions of single icosahedral phases (i-phase) and crystalline approximants in the Al–Pd–(Fe,Ru,Os) ternary systems. In the Al–Pd–Fe system, a single F-type i-phase is produced in a narrow composition region around Al71Pd18Fe11 in melt-spun ribbon samples, but it transforms to a (1/0)-cubic approximant on annealing at 600°C. In the Al–Pd–(Ru,Os) system, a structurally ordered i-phase is obtained on heating the melt-spun samples at a high temperature of 1000°C for 1 h in a composition region along e/a=1.8, but after prolonged annealing at the same temperature the i-phase transforms to a (1/0)-cubic approximant. A bulk single i-phase is also produced by annealing of the as-cast Al73Pd15Ru12 alloy at 1000°C.