Alloying elements characterisation in γ-based titanium aluminides by APFIM

The γ-based titanium aluminide intermetallics have been considered as one of the most promising candidate materials for elevated temperature applications. To improve poor ductility, β-stabilising elements such as Mn, Cr, V, etc., have been widely adopted as minor elements in γ-based titanium aluminide intermetallic alloys. In this paper, the alloy element partitioning is investigated in titanium aluminide intermetallics, with chromium as a third element. Both the conventional atom probe and the OPoSAP were used. All the alloys studied show near-lamellar structures. The element distribution of interstitials, as well as substitutional elements, have been determined for each phase in the alloys. Both interstitial and substitutional elements analysed in this study are found to be localised in the α2-phase. The degree of localisation for interstitials, however, is much more significant than that for substitutional elements.