A detailed X-ray line broadening study was made of ball-milled samples. It was observed that ball milling led to the formation of nanocrystalline grains, and partial transformation to a face-centered cubic Ti phase after milling for 10h. Milled samples exhibited an inhomogeneous strain which increased with increasing milling time. The origin of high strains was attributed to dislocations in the sample. The presence of a small number of stacking faults was noted, but their numbers did not vary much with milling time. Anisotropic line-broadening of the fault-unaffected reflections was explained in terms of an anisotropic dislocation contrast corresponding to <a> and <a + c> dislocations. Both edge and screw dislocations were predicted, with significant basal slip. A dislocation density of some 1011/cm2 was found in the milled samples.

An X-Ray Diffraction Study of Strain Localization and Anisotropic Dislocation Contrast in Nanocrystalline Titanium. P.Chatterjee, S.P.S.Gupta: Philosophical Magazine A, 2001, 81[1], 49-60