DISLOCATIONS AND GRAIN-SIZE IN BALL-MILLED IRON-POWDER

The microstructure of ball-milled iron powder has been investigated by high resolution X-ray line profile analysis. Analysis of line breadth s suggested that the contrast factors related to dislocations have to be taken into account in the Williamson-Hall procedure. This concluded to a modified Williamson-Hall plot which provided, in a straightforwa rd manner, the grain size refinement of nanocrystals ball-milled for d ifferent periods of time. At the same time it has been shown that stra in broadening, even in these nanoscale small-grain particles, is cause d by the presence of dislocations. The line profiles were also studied by the method of Fourier analysis, which gave the absolute values of dislocation densities.