X-Ray Microbeam Measurement of Local Texture and Strain in Metals

摘要

Synchrotron x-ray sources provide high-brilliance beams that can be focused to211u001esubmicron sizes with Fresnel zone-plate and x-ray mirror optics. With these 211u001eintense, tunable or broad-bandpass x-ray microbeams, it is now possible to study 211u001etexture and strain distributions in surfaces, and in buried or encapsulated thin 211u001efilms. The full strain tensor and local texture can be determined by measuring 211u001ethe unit cell parameters of strained material. With monochromatic or tunable 211u001eradiation, at least three independent reflections are needed to determine the 211u001eorientation and unit cell parameters of an unknown crystal. With broad-bandpass 211u001eor white radiation, at least four reflections and one measured energy are 211u001erequired to determine the orientation and the unit cell parameters of an unknown 211u001ecrystal. Routine measurement of local texture and strain is made possible by 211u001eautomatic indexing of the Laue reflections combined with precision calibration of 211u001ethe monochromator-focusing mirrors-CCD detector system. Methods used in 211u001eimplementing these techniques on the MHA-IT-CAT beam line at the Advanced Photon 211u001eSource will be discussed.