A New Icosahedral Al-Fe-Ta Alloy Prepared by Rapid Solidification

Abstract
A new icosahedral phase in the Al-Fe-Ta system has been produced by rapid solidification. The formation of the icosahedral phase is limited in the vicinity of 20%Fe and 10%Ta. The icosahedral phase consists of grains with a size of about 200 nm and each grain includes a high density of internal defects showing a contrast of radiating branches. Heating at 10 K/min gives rise to the decomposition of the icosahedral phase into Al3Fe and Al3Ta at about 900 K. It is thus concluded that the icosahedral phase has considerably higher thermal stability than Al-Mn and Al-Cr binary icosahedral alloys.