"BUTTERFLY" PRECIPITATES IN δ-＞TiN0.53-δ/-TiN0.53 ORDERING TRANSFORMATION0
(*General Research Institute for Non-Ferrous Metals，Beijing 100088
#Ecole Nationale Superieure de Chimie de Paris，75231 Paris，France)
#Ecole Nationale Superieure de Chimie de Paris，75231 Paris，France)
Abstract: The morphology of the hyperstoichiometric δ*-TiN0.53 long-range ordered precipitates during δ-TiN0.53—δ/TiN0.53 ordering transformation was investigated by transmission electron microscopy. It was found for the first time that theδ/-TiN0.53 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/TiN0.53 and in many other cubic-tetragonal phase transformalions. In general, δ/TiN0.53 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/TiN0.53 and their growth directions are parallel to<111) directions of the δ/TiN0.53 matrix.
Key words: "butterfly" precipitates δ/TiN0.53 ordering transformation