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

Effect of alloying on the nucleation and growth of laves phase in the 9-10% CR-3% CO martensitic steels during creep

Five Co-modified P92-type steels with different contents of Cr,W, Mo, B, N, and Re have been examined to evaluate the effect of the chemical composition on the evolution of Laves phase during creep at 650 C. The creep tests have been carried out at 650 C under various applied initial stresses ranging from 80 to 200 MPa until rupture. An increase in the B and Cr contents leads to a decrease in the size and volume fraction of M₂₃C₆ carbides precipitated during tempering and an increase in their number particle density along the boundaries. In turns, this affects the amount of the nucleation sites for Laves phase during cree