Effect of hot-rolling and heat-treatment conditions on the structure and mechanical and technological properties of nitrogen-bearing austenitic steel 05Kh22AG15N8M2F-Sh

The effect of hot-rolling conditions on the structure, strength, ductility, fracture toughness, and technological properties of the nonmagnetic steel 05Kh22AG15N8M2F-Sh containing 0.55% N has been studied. A homogeneous and fine-grained austenitic structure forms in the steel upon rolling at 1000–1050°C and a reduction of more than 60–70%. This structure provides the following properties: σ_0.2 = 1044 N/mm², σ_u = 1172 N/mm², δ = 32%, ψ = 64%, and KCV = 1.06 MJ/m² at ?70°C. The possibility of recrystallization of the hot-rolled steel (deformed at 10–90% reductions) is checked upon its subsequent heating to 850–1200°C followed by water quenching. The steel is shown to have high strength, ductility, and fracture toughness and to retain an austenitic structure without cracks or exfoliation upon hot plastic deformation by rolling up to a 90% reduction.     

Emission intensity in the visible and IR spectral ranges from Si-based structures formed by direct bonding with simultaneous doping with erbium (Er) and europium (Eu)

The photo- and electroluminescence spectra of silicon-based structures formed by direct bonding with simultaneous doping with rare-earth metals are studied. It is shown that emission in the visible and IR spectral ranges can be obtained from n-Si:Er/p-Si and n-Si:Eu/p-Si structures fabricated by the method suggested in the study. The results obtained make this method promising for the fabrication of optoelectronic devices.     

Effect of alloying with palladium on the electrical and mechanical properties of copper

Structure and physicomechanical properties of Cu–Pd alloys that contain 0.5–5.9 at % Pd have been studied. It has been shown that, in all alloys, a solid solution is formed; the lattice parameter of the fcc lattice and the electrical resistivity of the alloys grow linearly with an increase in the content of palladium. It has also been revealed that the introduction of palladium leads to an increase in the recrystallization temperature and to an increase in the strength properties. The assumption on the formation of an atomic short-range order in the quenched Cu–4.6 at %Pd and Cu–5.9 at %Pd alloys has been made.     

Small-Angle Acoustic Tomography under Shadow Testing with Antenna Arrays

Results of the experimental studies of an acoustic tract by the shadow testing method are provided. An inhomogeneous distribution of acoustic rays is revealed within the testing zone. The principle of producing a tomogram under small–angle probing is demonstrated. As a result of studying the error in determining the coordinates of flaws in different parts of the testing zone, it has been established that the least error corresponds to the flaw position at the center of the testing zone.     

Nickel saving in a 0Kh17N12M2-type (AISI 316) steel due to nitrogen alloying

The possibilities of the maximum decrease in the nickel content in an AISI 316 (0Kh17N12M2-type) steel via partial substitution of nitrogen for nickel and the corresponding correction of the contents of other alloying elements are analyzed. The corrected chemical composition of an AISI 316L-based steel is ≤0.02% C, 0.1–0.3% N, 17.5–18.5% Cr, 2.2–2.7% Mo, 3–4% Mn, and 0.1–0.5% Si. Calculation of the chromium equivalents of martensite formation and ferrite formation using the Potak-Sagalevich structure-phase diagram shows that, after quenching, these steels should have a purely austenitic structure without martensite or ferrite.     

Structure and properties of high-temperature austenitic low-carbon 01Kh15N22AG2V4TYu and 02Kh18N12AG11MFB steels

Principles of multicomponent alloying of high-temperature steels are formulated on the basis of reported and obtained experimental data. The short- and long-term strength, the structure, and the phase composition of high-temperature austenitic low-carbon steels 01Kh15N22AG2V4TYu and 02Kh18N12AG11MFB are studied in the structural states that form upon forging and aging and ensure the maximum hardening. These steels are found to have a high short-term strength and high-temperature strength. The tests of these steels performed for 8 × 10³ h without failure of specimens at a temperature of 680°C and stresses of 100–120 MPa show that they are promising materials that can operate at 620–680°C for 2 × 10⁵ h at a stress of 70 MPa in power units intended for operation at supercritical vapor parameters. The specific features of the fine structures of the steels in the forged and aged states that provide their high high-temperature strength are revealed. The evolution of structural constituents during long-term strength tests is studied, and the role of these constituents in fracture is determined.     

Effect of Plastic Deformation and Heat Treatment on the Structure and Hardening of Nitrogen-Bearing Steel 0Kh16AN4B

Metal Science and Heat Treatment -     

Ethane aromatization on Ga-Pt pentasil zeolites

Ethane aromatization on gallium-and platinum-modified pentasil zeolites (ZSM-5) with different framework constitutions was studied. The optimal zeolite composition and reaction conditions were determined and the synergistic effect of the promoters was revealed. The dependence of the catalyst activity on the SiO₂/Al₂O₃ molar ratio was established. The highest yield of aromatic hydrocarbons (～30%) and the highest selectivity for their formation from ethane (～63%) were attained on the (2%Ga–0.3%Pt)/HZSM-5 bimetallic catalyst having SiO₂/Al₂O₃ = 30.     

Pitting corrosion resistance of chromium-nitrogen steels with an overequilibrium nitrogen content

The effect of alloying elements, such as chromium and nitrogen (at their overequilibrium contents), and heat-treatment conditions (quenching from 1200°C, tempering at 400 and 600°C for 2 h) on the pitting corrosion resistance of chromium-nitrogen steels containing 15–21% Cr and 0.4–1.22% N in chloride solutions is studied. A relation is established between the structural and phase states of the chromium-nitrogen steels and the character of anode polarization curves and the potentials of pitting formation and repassivation. It is found that the pitting corrosion resistance of the chromium-nitrogen steels tempered at a temperature of 600°C decreases significantly because of the formation of chromium nitrides.