Fast x-ray microdiffraction techniques for studying irreversible transformations in materials.

Abstract

A pair of techniques have been developed for performing time-resolved X-ray microdiffraction on irreversible phase transformations. In one technique capillary optics are used to focus a high-flux broad-spectrum X-ray beam to a 60 {micro}m spot size and a fast pixel array detector is used to achieve temporal resolution of 55 {micro}s. In the second technique the X-rays are focused with Kirkpatrick-Baez mirrors to achieve a spatial resolution better than 10 {micro}m and a fast shutter is used to provide temporal resolution better than 20 {micro}s while recording the diffraction pattern on a (relatively slow) X-ray CCD camera. Example data from experiments are presented where these techniques are used to study self-propagating high-temperature synthesis reactions in metal laminate foils.