G. V. Shlyakhova

The distinctive feature of weld joints structure by adding the nanomodifying to the weld pool

The experimental studies were carried on for the test samples of welds of the steel 12X18H10T; the results are presented. The effect produced by the nanostructured modifying powders added to the weld pool on the quality of weld joints was examined. The weld joints were obtained by arc welding in argon atmosphere using consumable electrode. Due to the weld pool modification, the dendrite size was found to decrease and a more equilibrium microstructure would form in the weld material.

Changes in ultrasound velocity in the plastic deformation of high-chromium steel

The change in ultrasound velocity in the plastic deformation of high-chromium 40X13 stainless steel with ferrite–carbide structure (initially), martensite structure (after quenching), and sorbite structure (after high tempering) is investigated. The loading curve is different for each state. In the initial state, the loading curve is practically parabolic. In the martensitic state, linear strain hardening is the only stage. In the sorbitic state, a three-stage curve is observed. The structure of the steel after different types of heat treatment is studied by optical and scanning probe microscopy. In parallel with the recording of the loading curve, the change in properties of the ultrasonic surface waves (the Rayleigh waves) in the steel under tension is measured. To determine the speed of the Rayleigh waves, rectangular pulses (length 100 ns) are generated periodically at the input of the emitting piezoconverter and the wave is recorded after passage through the sample by the receiving piezoconverter, which is connected to a digital oscillograph. The resulting digital signal is used to measure the time from pulse generation to the appearance of a signal at the receiver output. The distance between the converters is constant. The changes in the ultrasound velocity during active loading are determined by the plastic flow—that is, by the stages in the corresponding loading diagram. The structure of the steel determines not only the type of deformation curve in uniaxial extension but also the dependence of the ultrasound velocity on the strain.

Microstructure of the elements of a superconducting Alloy Nb-Ti cable

The formation of a micro- and macrostructure in the Nb-Ti-based technical superconductors that are intended for the current-carrying elements in the magnetic system of the International Thermonu-clear Experimental Reactor and are subjected to deformation by drawing is considered. The deformation structure and microstructure of cable samples are studied by optical microscopy, atomic force microscopy, and scanning electron microscopy. The specific features of plastic flow localization at the sites of fracture of a multiconductor cable are revealed.

Evolution of Macro-Scale Plastic Flow Localization of Tri-Layered Stainless Steel - Low Carbon Steel - Stainless Steel Metal with Digital Image Correlation Method

Evolution of localized plastic deformation in tri-layered metal material casting consistng of the working part (layer) from austenitic stainless steel and bearing part from low-carbon steel was investigated. The pictures of localization of the plastic flow during the process of uniaxial tension were obtained by means of the digital image correlation method (DIC). Using optical microscopy methods, the changes in the fracture surface were investigated. The deformation diagrams were examined for deformed samples of tri-layered metal. These were found to show all the plastic flow stages: the linear, parabolic and pre-failure stages would occur for the respective values of the exponent n from the Lüdwik-Holomon equation. The analysis of the plastic flow stages and localized plastic deformation parameters was performed.

Plastic Deformation Macrolocalization. Local Stresses and Fracture in Ultrafine Grain Titanium

The process of plastic deformation in ultrafine grain titanium is considered. Using the methods of speckle photography and X-ray diffractometry, the distributions of local strains and of local elastic distortions were examined for the test sample work. It is shown that the method of atomic-force microscopy can be used effectively for qualitative and quantitative assessment of ultrafine grain material structure.

Nanostructure of superconducting Nb-Ti cable

Scanning-probe, electron, and optical microscopes are used to study the structural evolution in the intermediate stage of drawing (to diameter 1.3–1.2 mm) for superconducting cable based on Nb-Ti alloy (47.5 wt % Ti or, equivalently, 63.7 at % Ti). Such cable is used for current transmission in the magnetic system of the International Thermonuclear Experimental Reactor (ITER). The microstructure and phase composition of the superconducting alloy are investigated, as well as their influence on its properties after cold drawing and intermediate annealing. Zones where plastic deformation is localized are found at breaks in the super-conductor. The variation in shape and chemical composition of Nb-Ti fibers is studied in a defect-free region and in the fracture zone of the cable. A diffusional niobium barrier is identified around the Nb-Ti fibers in the copper matrix.

Localization of plastic deformation in alloyed γ-iron single crystals electrolytically saturated with hydrogen

On chromonickel γ-iron single crystals with

On the plastic flow localization of martensitic stainless steel saturated with hydrogen

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