Simulation of X-ray diffraction-line broadening due to dislocations in a model composite material

X-ray diffraction-tine profiles of two-dimensional, plastically deformed mo del composite materials are calculated and analysed in detail. The composit e consists of elastic reinforcements in a crystalline solid and is subjecte d to macroscopic shear. Slip occurs in the matrix only due to the collectiv e motion of discrete dislocations on a single set of parallel slip planes. The results of dislocation dynamics computations are used as input for the calculation of the line profiles. The line profiles are computed directly u sing the kinematics approach, without making a priori assumptions on the di slocation distributions. Two steps are required. First, the fall intensity distribution of a single crystal of composite material is calculated. Then, assuming a perfectly random orientation distribution of such single crysta ls, powder diffraction-line profiles are determined. Results will be presen ted for several orders of reflection and in different crystallographic dire ctions. The broadening of the line profiles is shown to be not only determi ned by the density of dislocations, but also by their spatial distribution. (C) 2001 Elsevier Science B.V. All rights reserved.