Microstructure and properties of fine grained Cu-Cr-Zr alloys after termo-mechanical treatments

Cu-Cr-Zr alloys provide an excellent combination of strength and electric conductivity and are frequently used as engineering materials in various electric/electronic devises. The present review deals with the microstructural design of Cu-Cr-Zr alloys, their alloying concept, thermo-mechanical processing based on technique of severe plastic deformation, physical mechanisms responsible for high strength and electric conductivit

Deformation microstructures, strengthening mechanisms, and electrical conductivity in a Cu-Cr-Zr alloy

Cr-0.06%Zr alloy subjected to multiple equal channel angular pressing (ECAP) at temperatures of 473-673 K were investigated. The new ultrafine grains resulted from progressive increase in the misorientations of strain-induced low-angle boundaries during the multiple ECAP process. The development of ultrafine-grained microstructures is considered as a type of continuous dynamic recrystallizatio

Nitrogen adsorption on graphene sponges synthesized by annealing a mixture of nickel and carbon powders

The present research has been supported by the National Research Programme for 2014–2017 “Multifunctional Materials and Composites, Photonics and Nanotechnologies”.Adsorption by graphene sponge (GS) manufactured by annealing nickel-carbon powder mixture in inert atmosphere has been studied. By determining the specific surface area (SSA) for the GS sample, it has been found that Brunauer, Emmett, Teller method (BET) of approximation of experimental isotherms gives wrong results in the pressure range of 0.025-0.12 because adsorption in this pressure region is affected by walls of ampoule. Real SSA value has been found by subtracting pore effect method (SPE) or by BET approximation in a low range of relative pressure of 0.0004-0.002.Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Microstructure evolution in a Cu-Cr-Zr alloy during warm intense plastic straining

The effect of equal channel angular pressing at a temperature of 200°C to a total strain of 12 on microstructure evolution and mechanical properties of a Cu-0.87wt.%Cr- 0.06wt.%Zr was investigated. New ultrafine grains resulted from gradual increase in the misorientations of strain-induced low-angle boundaries with increasing number of passes. Therefore, the development of ultrafine grains is considered as a kind of dynamic recrystallization. The equal channel angular pressing to a total strain of 12 resulted in the formation of almost equiaxed ultrafine grained structure with an average grain size of 0.5 Tm and 0.7 Tm in the solution treated and aged samples, respectively. At the same time, the fraction of ultrafine grains comprises 0.77 in the solution treated samples and 0.72 in the aged samples. Significant grain refinement led to the remarkable increase of the ultimate tensile strength up to 550 MP

On the fracture behavior of a creep resistant 10% cr steel with high boron and low nitrogen contents at low temperatures

An advanced, high chromium, creep-resistant steel was subjected to the tensile tests and three-point bending tests of Charpy V-notch specimens at temperatures of-196 to 20 °C. The steel exhibited ductile fracture under tension tests at all of the temperatures studie

Synthesis and structure of 2′-substituted 1-(1,3-dioxan-5-yl)uracils. Positive role of the Eu(fod)3 nmr shift reagent

The configuration of 1-(2-R-1,3-dioxan-5-yl)uracils and the conformation of the dioxane ring in these compounds were investigated by 1H NMR spectroscopy with the aid of the Eu(fod)3 shift reagent. It is shown that the dioxane ring exists in the preferred chair conformation with an axial orientation of the pyrimidine ring; this is confirmed by the resonance of the 5′-Ha proton in the form of a broad singlet with υ1/2υ8.5 Hz. An analysis of the spectral peculiarities of the synthesized compounds made it possible to establish the orientation of the substituents attached to the second C2 steric center. The three-dimensional structure of 1-(2, 2-dimethyl-1,3-dioxan-5-yl)uracil was determined by an x-ray diffraction study, and the axial orientation of the pyrimidine ring was confirmed. It is shown that significant flattening of the carbon part of the ring (ψ = 46.6 °) is observed in this molecule. An intramolecular (C6...O1, = 3.05 Å) hydrogen bond was observed in the molecule of this compound. © 1982 Plenum Publishing Corporation

Measurement of tensor analyzing powers in deuteron photodisintegration

New accurate measurement of tensor analyzing powers T20, T21 and T22 in deuteron photodisintegration has been performed. Wide-aperture non-magnetic detectors allowed to cover broad kinematic ranges in a single setup: photon energy = 25 to 600 MeV, proton emission angle in CM = 24 to 48 deg. and 70 to 102 deg. New data provide a significant improvement of a few existing measurements. The angular dependency of the tensor asymmetries in deuteron photodisintegration is extracted for the first time.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

Increase of precision of casting blocks by applying acoustical oscillations in gas-impulsive moulding

The present article shows the results of the theoretical and empirical research of the study of the impact made by acoustical oscillations on the working process of a gas-impulsive moulding device with the purpose of increasing the quality of the casting blocks’ seal and decreasing the roughness of the surface of a casting block. It has been shown that acoustical oscillations intensify the working process of the gas-impulsive moulding device. With the increase of frequency and power of oscillations the hardness of a casting block first sharply rises, but then gradually decreases. It has been found out that oscillations may help to adjust the precision of a casting block due to high sensitivity of a gas-impulsive process to the frequency of oscillations. The use of acoustical oscillations broadens technological opportunities of the moulding device