Improved X-ray and electron diffraction methods for twin determination in hexagonal crystals

Two improved methods of characterizing twin orientations in deformed crystals have been developed and compared; the back-scattered Kikuchi electron diffraction method in a standard scanning electron microscope and a new high-resolution X-ray pole-figure technique. Comparative tests on titanium and magnesium crystals deformed in plane strain compression up to high strains demonstrate their complementary features. The back-scattered Kikuchi diffraction technique, which combines imaging and microdiffraction, is well adapted to localized twin-orientation studies in both single and polycrystals after careful surface preparation. The high-resolution X-ray pole figures can be used for more quantitative studies of twinned volume fractions, including very fine twins, in crystallographically oriented samples such as deformed single crystals or large-grained polycrystals.