Distribution behaviour of alloying elements in α2(α)/γ lamellae of TiAl-based alloy

Primary α2(α)/γ lamellae structure in a Ti–47Al–2Nb–1Cr–1V alloy (in at.%) was obtained depending on different cooling rates from the high-temperature α single phase region after the alloy was solution treated there. Atom probe (AP) microanalysis and TEM with electron energy loss spectroscopy (EELS) were run to examine the partitioning behaviour of Nb, Cr, V, O and C in the high-temperature α/γ lamellae. The results show that V and Cr, and interstitial elements C and O are enriched in the high-temperature α phase, while Nb is homogeneous in the two phases. The EELS result qualitatively agrees with that of AP microanalysis. No segregation of these alloying elements was detected along the observed high-temperature α/γ interface.