A TEM study of the habit plane structure of intragrainular proeutectoid α precipitates in a Ti–7.26 wt%Cr alloy

The crystallography and the structure of the habit plane of proeutectoid alpha precipitates in beta matrix in a Ti-7.26 wt%Cl were studied using TEM. The orientation relationship was found to deviate slightly from the ideal Burgers orientation relationship. The habit plane of precipitates was found to be normal to a particular set of Deltag's. A set of dislocations, about 11 nm apart, were observed on the habit plane of the precipitates. The Burgers vector of the dislocations, as determined by g (.) b contrast analyses, is [1 -11](beta)/2([2-1-13](alpha)/6). This Burgers vector is different from those determined by previous investigations. The observations are discussed in terms of an analytical O-line model and tend to Support the prediction of the O-line model. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.