A closely-complete peritectic transformation during directional solidification of a Ti-45Al-8.5Nb alloy

Solidification and grain refinement in Ti45Al2Mn2Nb1B

“…Peritectic reaction is a rarely touched topic in TiAl research but it was indeed observed in some directionally solidified high Nb, Ta-containing TiAl alloys [11,12]. The peritectic alpha was expected to have some orientation relationship with the beta dendrites since the latter in fact act as the substrates for peritectic alpha nucleation during peritectic reaction.…”

“…This rationale has been confirmed by the observation in Ti4522 and the Burgers orientation relationship is prevailing. The peritectic alpha was speculated by some researchers to have a grain refinement effect since it could have various orientations even within the same interdendritic area [12]. Indeed differently oriented peritectic alpha grains can form within the same interdendritic area and they can influence the orientation when the adjacent beta dendrite transforms into alpha but grain refinement in this way has not been observed yet.…”

“…It implies that they were alpha already before quenching and quenching only had the alpha phase transformed into alpha2 and retained (or transformed into fine gamma lamellae in the interdendritic areas). The existence of the alpha in the interdendritic areas suggests that the L þ b / a peritectic reaction should have occurred [11,12].…”

Response of the solidification microstructure of a high Nb containing TiAl alloy to an isothermal high-temperature heat treatment

“…indicated that the growth of peritectically-transformed a phase could lead to coarse lamellar colonies [20]. In dendrite cores, the grain size is much smaller than that in interdendritic regions.…”

Temperature Gradient Estimation of Floating Zone Furnace by Mean Lamellar Spacing Measurement in DS-processed TiAl Alloys

“…al) DS-processed alloys and related mechanical properties using both FZ and Bridgman type [4][5][6][7][8].…”