On the formation of intermetallics in Fe–Al system – An in situ XRD study

• Published in: Intermetallics Vol. 32; pp. 127 - 136
• Main Authors: Novák, Pavel, Michalcová, Alena, Marek, Ivo, Mudrová, Martina, Saksl, Karel, Bednarčík, Jozef, Zikmund, Petr, Vojtěch, Dalibor
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2013
• Subjects: A. Iron aluminides (based on FeAl); C. Powder metallurgy, including consolidation; C. Reaction synthesis; F. Diffraction (electron, neutron and X-ray); C. Reaction synthesis; A. Iron aluminides (based on FeAl); F. Diffraction (electron, neutron and X-ray); C. Powder metallurgy, including consolidation
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2012.08.020

Self-propagating high-temperature synthesis (SHS) was previously proposed as alternative preparation route for Fe–Al intermetallics. However, this process was not optimized and the mechanism and kinetics of the phases' formation was not fully clarified up to current days. In this work, in situ high energy X-ray diffraction analysis was carried out during the SHS process and the mechanism of the intermetallic' formation in FeAl25 powder mixture was described during rapid heating and isothermal annealing at 800 °C as well as during a slower continuous heating to 900 °C. During slower heating, the formation of Fe2Al5 and FeAl2 intermetallics starts below the melting point of aluminium. When the heating rate is high, intermetallics are created after melting of aluminium. During long-term annealing, all of the phases can be transformed to FeAl phase when fine powders were applied. Detailed mechanism is proposed in this paper and kinetics of the intermetallics' formation is described. [Display omitted] ► In situ high energy XRD analysis was carried out during SHS of Fe–Al. ► Initiation temperature of Fe + Al reaction depends on heating rate. ► Mechanism of intermetallics' formation during SHS was proposed. ► Fe2Al5 and FeAl formation kinetics was studied by macro-scale model of SHS.