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The effects of positive and negative temperature and static load on the main informative parameters (structure coefficient, partial energy, location) of acoustic emission (AE) signals, which determined the mechanism for changing the structure of carbon fiber and the beginning of its destruction, are investigated. Tests of specimens of carbon fiber T800, made of nine monolayers with laying [±45/90/О3/90/±45], size 600x100x0.9 mm. Each sample was subjected to static loading and the effects of positive (+20, +40, +60, +80, +100 °С) or negative (–20, –40, –60, –80 °C) temperatures in the area of the concentrator in the form of a 12 mm diameter hole. Using fractography, changes in the structure of carbon plastic from the applied static load and temperature and changes informative parameters were analyzed. It was shown that the lamination of the material with simultaneous exposure to static load and temperatures from –80 to –20 °C and from +60 to +100 °C corresponded to an increase in the structural coefficient and partial energy, which caused an energy shift in the frequency range 125…250 kHz. Under the same static loads, but temperatures of +20 and +40 °C, informative parameters took on minimal values, that meant the energy was shifted to the frequency range 250…500 kHz, characterized the crumbling of the matrix and breaking of the fibers without lamination of the CFRP. Under all temperature conditions, the location of the signals began in the hole area and spread in the direction of the static load. The detection the disturbance of the CFRP structure by the informative parameters of AE signals makes it possible to reduce the risk of emergency situations during working of the composite construction.

Relationship between the main informative parameters of acoustic-emission (AE) signals recorded during static loading of a CFRP sample and the process of material fracture has been investigated. Clusterization of AE signals by digitized shape has made it possible to locate a zone they originate from. Material was then cut out from this zone to prepare thin sections that were subjected to fractography. Fractography revealed fiber fracture, brittle cracking of the matrix, its exfoliation from the carbon fibers, etc.

In this work the study of the friction stir welding process of 2 mm thick aluminum alloy AA2024 sheets cut along and across the rolling direction was carried out. The obtained results show that the rolling direction of AA2024 sheet workpieces has a significant effect on the selection of optimal welding modes. It is revealed that at welding across the rolling direction it is possible to achieve the highest values of the ultimate tensile strength in a rather wide range of modes.

The work compares the strength characteristics and microstructure of 2-mm-thick welded joints from Al-Mg alloy AA5056, produced by friction stir welding along and across the workpiece rolling direction. The tests show that the variation of parameters results in the formation of a complex structure, which is determined by the contribution of both mechanical and thermal components. Depending on the rolling direction, the welded joint has different mechanical properties under identical conditions. In the case of the rolling direction coinciding with the friction stir welding direction, the strongest welded joint has the ultimate tensile strength of 328 MPa, which is equal to 98% of the base metal strength. In case of welding in the transverse direction, the ultimate tensile strength of the joint exceeds those of the base metal by 8 MPa and is equal to 333 MPa. According to the conducted experiments it was proved that the structure and strength of friction stir welded joints depends on the workpiece rolling direction, which implies different welding parameters for these cases.

Residual stresses in rolled tungsten after pulsed irradiation with a plasma and an electron beam at the GOL-3 facility were measured. The mechanical stresses were derived from the strain, which was measured by the change in the interplanar distance in different directions. The interplanar distance was gaged from the shift of the peak of diffraction scattering of X-rays. The measured tension turned out to be a tensile stress along the surface. The tension along the direction of rolling and grinding was approximately three times larger than that in the perpendicular direction. The work was carried out at the VEPP-3/VEPP-4 complex.

The evolution of the perlite structure in the course of plastic deformation of U8 and St70 steels has been studied. With increasing degree of cold working, the dislocation density increases near the interphase boundary in the ferrite interstices of perlite, which forms a dislocational “fringe”, which in turn forms a pseudocellular structure. Under thermal deformation conditions, a subgrain structure arises in the ferrite interstices of lamellar perlite. The most dangerous localized flow channels in which plasticity is exhausted for the first time and cracks appear, are the deformation bands. The narrower the deformation bands and the larger the value of the relative displacement of the subcolumn blocks adjacent to them, the more dangerous they are with regard to failure. The features revealed in the development of deformation and failure provides a basis for controlling steel treatment regimes in order to produce perlite with the optimum structural parameters.