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 Al 3 Fe and Al 3 Ta 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.