Mechanism of the Intermediary Phase Formation in Ti-20 wt. % Al Mixture during Pressureless Reactive Sintering

Andrea Školáková; Pavel Salvetr; Pavel Novák; Jindřich Leitner; Davy Deduytsche

doi:10.3390/ma12132171

Mechanism of the Intermediary Phase Formation in Ti-20 wt. % Al Mixture during Pressureless Reactive Sintering

Materials (Basel). 2019 Jul 6;12(13):2171. doi: 10.3390/ma12132171.

Authors

Andrea Školáková¹, Pavel Salvetr², Pavel Novák², Jindřich Leitner³, Davy Deduytsche⁴

Affiliations

¹ Department of Metals and Corrosion Engineering, University of Chemistry and Technology, Technická 5, 166 28 Prague 6, Czech Republic. skolakoa@vscht.cz.
² Department of Metals and Corrosion Engineering, University of Chemistry and Technology, Technická 5, 166 28 Prague 6, Czech Republic.
³ Department of Solid State Engineering, University of Chemistry and Technology, Technická 5, 166 28 Prague 6, Czech Republic.
⁴ Department of Solid State Sciences, Ghent University, Krijgslaan 281 S1 9000 Gent, Belgium.

Abstract

This work aims to describe the mechanism of intermediary phases formation in TiAl20 (wt. %) alloy composition during reactive sintering. The reaction between titanium and aluminum powders was studied by in situ diffraction and the results were confirmed by annealing at various temperatures. It was found that the Ti₂Al₅ phase formed preferentially and its formation was detected at 400 °C. So far, this phase has never been found in this alloy composition during reactive sintering processes. Subsequently, the Ti₂Al₅ phase reacted with the titanium, and the formation of the major phase, Ti₃Al, was accompanied by the minor phase, TiAl. Equations of the proposed reactions are presented in this paper and their thermodynamic and kinetic feasibility are supported by Gibbs energies of reaction and reaction enthalpies.

Keywords: aluminides; in situ diffraction; mechanism; powder metallurgy; reactive sintering.

Grants and funding

21-SVV/2019/Ministerstvo Školství, Mládeže a Tělovýchovy