Icosahedral phase in rapidly solidified Al–Fe–Ce alloy

To study the mechanisms for the high strength of Al–TM–Re alloys, we synthesized metallic glasses Al90Cu5Ce5 and Al90Fe5Ce5 by melt spinning. Icosahedral particles surrounded by f.c.c.-Al were found to appear as a primary precipitation phase in the amorphous Al90Fe5Ce5 alloy. The mechanical properties of the amorphous Al90Fe5Ce5 alloy can be enhanced by using a mixed structure of icosahedral nanoparticles, Al nanoparticles and amorphous matrix. Microstructure analysis suggests that icosahedral structural units are homogeneously distributed in the matrix of the amorphous Al90Fe5Ce5 alloy. These structural units can be identified by the characteristic isothermal calorimetric signals associated with their transformation to fine quasicrystalline grains. The unusual glass formability of the Al–Fe–Ce alloy is discussed in this report. A distinct pre-peak is observed in the X-ray diffraction patterns of the amorphous Al90Cu5Ce5 and the Al90Fe5Ce5 alloys. The relaxation and glass transition phenomena are clearly observed for the Al90Cu5Ce5 alloy. Based on the structure difference between Al90Fe5Ce5 and Al90Cu5Ce5, the origin of the pre-peak can be attributed to the inter-metallic compounds pre-existent in the amorphous matrix.