HIGH-TEMPERATURE STABILITY AND FACETING OF THE ICOSAHEDRAL AL-FE-CU PHASE

Thin fragments of dodecahedral particles, extracted from an as-cast Al65Fe15Cu20alloy ingot, have been studied by transmission electron microscopy. The as-cast state is not icosahedral but trigonal and exhibits a microstructure such that the overall symmetry is pesudo-icosahedral; annealed within the microscope, this microcrystalline state transforms homogeneously into the icosahedral phase, stable until its melting point. During this second transformation (surface melting or sublimation), faceted holes of a dodecahedral shape were observed to develop within the quasicrystalline phase. © 1990 Taylor & Francis Group, LLC.