Evaluation of anisotropic small-angle neutron scattering data from metastable β-Ti alloy

Small-angle neutron scattering (SANS) data from single-crystal metastable beta-Ti alloys exhibit an anisotropic character with interparticle interference maxima due to ordering of the dense system of omega particles. For an evaluation of such data, the program NOC (previously used for evaluation of data from dense ordered gamma ' precipitate system in single-crystal nickel-based superalloys) was well suited. Nevertheless, an improvement of this evaluation program was necessary in its model-forming part. A further change of the evaluation program concerned the mode in which the size distribution was calculated. This upgrade is presented. The improved NOC program was employed for the evaluation of SANS data of annealed metastable single-crystal beta-Ti alloy containing omega particles. 3D fit in reciprocal space was successfully used. A model of ellipsoids did not lead to a better fit than a model of particles with the spherical shape. The microstructural parameters of omega particles were determined.