Abstract:The morphology of the hyperstoichiometric δ*-TiN_0.53 long-range ordered precipitates during δ-TiN_0.53—δ^/TiN_0.53 ordering transformation was investigated by transmission electron microscopy. It was found for the first time that theδ^/-TiN_0.53  ordered precipitates present a "butterfly" microstructure, which is greatly similar to that found in some martensite transformations, but quite different from the general lamellar microstructures observed in stoichiometricδ^/TiN_0.53  and in many other cubic-tetragonal phase transformalions. In general,  δ^/TiN_0.53  precipitates consist of three "butterfly" branches whose geometrical symmetry axes are intersected one another at a common point, these "butterflies" are all formed by the three equivalent orientation domains of the δ^/TiN_0.53  and their growth directions are parallel to<111)  directions of the δ^/TiN_0.53  matrix.

Key words: "butterfly" precipitates  δ^/TiN_0.53  ordering transformation