Icosahedral phase formation in rapidly quenched aluminum--ruthenium alloys

Systematic rapid quenching experiments on the icosahedral phase-forming system Al1√/sub x/Ru/sub x/ were performed for x<20 at. %. The solidified alloys have been studied by electron microscopy and x-ray diffraction to determine their composition, constituent phases, and phase morphology. It has been determined that the icosahedral phase must form directly from the liquid and, at these quench rates, is always found in the presence of second or third phases. The results have been summarized in a metastable phase diagram appropriate for rapid solidification of Al1√/sub x/Ru/sub x/ at piston and anvil quench rates. This metastable phase diagram describes the results for Ru concentrations less than 14 at. %