Crystallographic features of the primary Al₃Fe phase in as-cast Al–3.31wt% Fe alloy

Abstract

The preferred crystallographic extension directions of the primary Al 3 Fe phase formed during the solidification of the Al–3.31wt% Fe alloy have been confirmed as 〈010〉 or 〈011〉. Two sorts of twins related to the extension directions were found and their complete twinning elements determined. The morphologies of the primary Al 3 Fe phase related to the crystallographic extension directions and twinning modes are analysed. The crystallographic surface planes binding the primary phase in the extension directions are identified. The formation of the twins is attributed to these surface planes.