Microstructure evolution of high strength AlFeVTi nanoquasicrystalline alloys at elevated temperature

The stability of a series of Al92Fe3V3Ti2 nanoquasicrystalline alloys produced with decreasing cooling rates was investigated. As-cast microstructure in rapidly solidified ribbons varied from a mixture of 5 nm granular amorphous phase and Al grains at the highest cooling rates, to a composite microstructure consisting of a dispersion of 200–300 nm diameter quasicrystals and intermetallic phases at the lowest cooling rate. In situ monitoring of phase transformations in thick samples, during annealing up to 873 K, was done using high-energy diffraction studies at the European Synchrotron Radiation Facility (ESRF), Grenoble, France. The nanoquasicrystalline phase was found to be stable even in low quench rate alloys up to temperatures of 420 °C, decomposing into more stable intermetallic phases through intermediate stages at which approximant crystalline phases are formed.