We present the results of experimental studies of the return of Ni–Fe–Ga–Co and Cu–Al–Ni single crystals to the initial form at the macro- and microlevels after their deformation by compression and subsequent restorative heating. It is found that the geometric dimensions of the sample are reproduced with high accuracy (up to 20 μm). The microrelief appearing on the initially polished surface during crystal compression (the arithmetic mean profile deviation R _ a ≈ 0.25–0.75 μm, the average spacing of local protrusions of the profile S ≈ 0.027–0.11 mm) is not removed by subsequent heating and remains with further multiple repetition of deformation–restoration cycles.

The process of growing crystals of the Ni-Fe-Ga-Co alloy by the Stepanov method has been developed. It was found that the structural perfection is disturbed by the formation of dendrites, which are distributed inhomogeneously both along the length and in the cross sections of the crystals. The blocking effect on the dendrites of crystals of the martensite phase, which appears when the samples are cooled to the temperature of the transition of the crystal to the martensite state, is found. The elemental composition of dendritic formations was studied and it was shown that the iron content in the dendrite is approximately 30% higher, and the gallium content is 40% lower than in the matrix. Based on the modeling of heat transfer processes in the real growth zone, taking into account the experiments performed, recommendations were obtained for suppressing the formation of dendrites

The article deals with the measurement of residual stresses that are formed in shaped sapphire single crystals when they are grown from a melt. An algorithm is developed for calculating the normal components of the residual stress tensor from the data of optical measurements of residual stresses by the conoscopy method for optically uniaxial crystals in the form of plates. Examples of measuring residual stresses and calculating normal components for a square rod and a basal-faceted sapphire ribbon are given. It is shown that normal stresses are concentrated mainly along the periphery of the plates and reach up to 25 MPa in the rod and 70 MPa in the strip.

Accumulation of defects in the synthetic quartz single crystal has been investigated at the early stages of deformation. Process is studied with the help of three independent nondestructive methods, namely: acoustic emission, X-ray computed tomography and synchrotron radiation topography. It is shown that results obtained by the three methods are consistent with each other, allow detecting the area of defect formation and, what is more important, to match acoustic emission parameters with the ones of defects. This result is of practical importance, since it makes it possible to further identify areas of fracture growth and estimate their size in situ only by analyzing acoustic emission data in cases where the use of other control methods is impossible.