Investigation of texture and dislocation density in rolled beta-brass by X-ray and neutron diffraction

In order to calculate the dislocation density from the broadening of diffraction profiles following the theory of Krivoglaz [1,2] and Wilkens [3] it is necessary to know the mean orientation factor chi which depend on the individual slip system, the type and Burgers vector b of the dislocations, the diffraction vector g and the elastic moduli C-ij. Because of the deformation of beta-brass several slip systems were proposed to appear at different temperatures [4] the idea realized in the present work was to roll beta-brass at room temperature (RT) and 300 degrees C to different strains, to measure the texture and to compare it with simulated textures using the different slip systems. It could be shown that the (211)[11 (1) over bar] slip system is preferred especially at higher deformation degrees and also at elevated temperatures. Simulation by using only non-[111] Burgers vectors does not fit the experimental textures at all. If only the (110)[(1) over bar 11] slip system is activated the ideal orientation {001}[1 (1) over bar 0] decreases with increasing strain which equals the behaviour at low strains at RT and is contrary to that at 300 degrees C. Accordingly, the dislocation densities were determined by assuming only [111] superdislocations of screw character. The dislocation densities determined with the diffraction vector in normal direction of the rolling plane do not fit the Taylor equation with a fixed constant a of the dislocation interaction which is in agreement to the observed increase of the sphere of the strain field of a single dislocation. (C) 1997 Elsevier Science S.A.