Abstract
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Synchrotron X-ray diffractometry is demonstrated to be an effective characterisation tool for resolving mesoscopic structures of nanocrystalline powders prepared by ball milling. In this work the high energy, highly monochromatic x-ray radiation from the high-resolution powder diffractometer on beamline BL-20B of the Photon Factory was used for the structural analysis of ball-milled materials. From a large number of mechanically alloyed samples the most representative have been selected for this experiment e.g. samples that do not show clear structural information using conventional x-ray analysis. For these samples accurate structure and grain size analysis were performed. The high resolution and low background achieved by the synchrotron instrument reveal clear crystalline features in powder data from mechanically alloyed materials for which conventional laboratory x-ray equipment shows only amorphous -like patterns. Peak width analysis determined the grain sizes to be 10.6 nm for V and 8.6 nm for Ti powders milled in an ammonia environment.