Determining the orientation of parent β grain from one α variant in titanium alloys

The relationship between the crystallographic orientation and habit plane normal of transformed alpha laths in titanium alloys is discussed according to the Burgers orientation relationship and the three-dimensional structure of the alpha lath. A new method (orientation-trace method) is developed to determine the orientation of the parent beta phase using the orientation of the alpha lath, which was measured by electron backscatter diffraction, and the microstructural morphology of that alpha variant. This approach is validated in a near-alpha titanium alloy. Moreover, the habit plane normal direction of the transformed alpha lath can be obtained from the crystallographic orientations of the a lath itself and its parent beta grain. The verification and the corresponding discussion show the reliability of this approach.