Interparticle interference and elastic interphase deformations upon X-ray scattering by precipitates statistically distributed in a crystal: III. Analysis of results of applied investigations

Abstract

Based on theoretical data [1, 2], results of X-ray diffraction investigations of the initial stages of decomposition of Fe-25Ni-25Al and NaCl-AgCl solid solutions have been analyzed critically. It has been established that the interpretation of diffuse effects in diffraction patterns of the Fe-Ni-Al alloy in terms of the three-phase model is wrong; numerous errors and inaccuracies have been revealed in the representation and explanation of diffuse scattering in works devoted to the NaCl-AgCl alloys. A new interpretation of effects of diffuse scattering is given and a quantitative estimation is given to the structural parameters of alloys and elastic interphase stresses. It is shown that diffraction triplets consisting of relatively wide maxima caused by scattering by the matrix and precipitates and of a peaked maximum caused by scattering by both phases can be formed in the fundamental reflections of alloys with precipitates isomorphic to the matrix. Kinetic and structural factors that determine the formation of high magnetic properties, including the high coercive force and magnetic saturation, in the Fe-Ni-Al alloy are discussed. The necessity of a further reconsideration of the results of investigations that rest upon the three-phase model of solid-solution decomposition when interpreting diffuse scattering is noted.