Abstract <p>The article presents the results of modeling the three-dimensional distribution and accumulation of deformation defects in the volume of a single-crystal intermetallic compound with the <i>L</i>1₂ superstructure during deformation by uniaxial compression. The calculations are performed in a multilevel model of synthesis of dislocation kinetics and mechanics of a deformable solid for cases of deformation with and without taking into account the forces of end friction. The patterns of distribution of the intensity of plastic strain and the density of dislocations in the plane of the central longitudinal section of a deformed rectangular sample are presented. In a numerical experiment, brittle fracture of a deformed sample is obtained at a degree of strain close to the value of full-scale experiment. The influence of the end friction forces on the features of shape change and fracture of a single-crystal sample is analyzed. It is shown that due to the influence of end friction forces, a noticeable decrease in the degree of brittle fracture strain occurs. A statistical assessment of the degree of homogeneity of the distribution of deformation defects in the deformed volume is carried out. A comparison of the results of the numerical experiment obtained in the work with the results of mechanical tests and studies of the deformation relief of Ni₃Ge single-crystal intermetallic compound with the <i>L</i>1₂ superstructure shows good agreement.</p>