Diffuse scattering of electrons in the alloy Ti$_{50}$Ni$_{46}$Nb$_{4}$ during the pre-precipitation of the X-phase

The method of diffraction electron microscopy is used to study the fine crystalline structure of the B2 solid solution in the alloy Ti$_{50}$Ni$_{46}$Nb$_{4}$. During an isothermal anneal at 550°C the X-phase with the face-centered cubic structure and lattice constant a$_{x}$= 2√7a$_{B2}$=15,8A precipitates. Immediately after hardening of the alloy at 1100°C the body-centered cubic B2 lattice contains regions with crystal structure close to the structure of the X-phase, which are responsible for the characteristic configuration of the intense diffuse electron scattering.