Distribution behaviour of alloying elements in alpha(2)(alpha)/gamma lamellae of TiAl-based alloy

Primary alpha(2)(alpha)/gamma lamellae structure in a Ti-47Al-2Nb-1Cr-1V al loy (in at.%) was obtained depending on different cooling rates from the hi gh-temperature a single phase region after the alloy was solution treated t here. Atom probe (AP) microanalysis and TEM with electron energy loss spect roscopy (EELS) were run to examine the partitioning behaviour of Nb, Cr, V, O and C in the high-temperature alpha/gamma lamellae. The results show tha t V and Cr, and interstitial elements C and O are enriched in the high-temp erature cc phase, while Nb is homogeneous in the two phases. The EELS resul t qualitatively agrees with that of AP microanalysis. No segregation of the se alloying elements was detected along the observed high-temperature alpha /gamma interface. (C) 2000 Elsevier Science Ltd. All rights reserved.