A band microstructure in directionally solidified hypo-peritectic Ti–45Al alloy

We report the first experimental observation of discrete bands in directionally solidified hypo-peritectic Ti–45Al alloy. The banded structure consists of two phases and the lamellar orientation within these phases is different. Lamellar boundaries within one phase inclined at an angle of 45° to the growth direction and within the other phase aligned parallel to the growth direction. A number of models were proposed to explain the band formation in TiAl alloys. It was found that the phase precipitation in hypo-peritectic TiAl alloys was influenced by the solidification condition and the growth morphologies between primary and peritectic phases.