Re-determination of transition temperatures in the Fe–Al system by differential thermal analysis

Abstract

Abstract The Fe – Al phase diagram has been experimentally re-investigated by differential thermal analysis on 64 alloys with different compositions in the concentration range between 0 and 74 at.% Al. For the melting temperatures, the existence of a shallow maximum at low Al-contents is proven experimentally for the first time. In the solid state, critical temperatures and invariant reactions as well as the order/disorder and ferro-/paramagnetic transitions occurring in the Fe-rich part of the binary system are studied in detail. For the most part, the present data confirm recent assessments of the Fe – Al phase diagram. Small corrections are suggested for some of the critical temperatures. Several effects related to the re-arrangement and annealing out of defects in the B2-ordered FeAl phase are also described. No effect which could be related to the K state has been found. Instead an effect was observed in the same temperature range but for a much wider range of compositions, which is probably due to the formation/dissolution of Fe3AlC precipitates.