Reciprocal space analysis of β phase precipitates in a TiAlW alloy

TiAlW alloy is investigated by transmission electron microscopy. There are β precipitates at the lamellar interface after aging heat treatment. β precipitate is a bcc structure. The orientation relationship between β and γ phase is 〈 1 ¯   0   1 〉γ//〈1 1 1〉β, (1 1 1)γ//( 1 ¯   1   0 )β. When the incident electron beam is along [1 1 1]γ, six different β phase variants are observed. The long axis directions of β precipitates are discussed according to reciprocal space O Lattice model. The predictions from the model are in good agreement with the experimental observations.