—The effect of annealing temperature on the structure, texture, and mechanical properties of the austenitic 08Kh16N13M2T stainless steel after cold radial forging to a degree of 95% has been ...investigated. Preliminary plastic deformation results in the formation of austenitic structural and 〈111〉 and 〈100〉 textural gradients. Low-temperature annealing (500–600°C) causes structural polygonization. The intensity of the 〈111〉 and 〈100〉 textural components remains unchanged. Annealing at 700°С initiates recrystallization only in the surface layers of the bar. Annealing at 800–900°C results in static recrystallization processes throughout the bar cross section, which blurs the textural gradient. Annealing at 400–600°C increases the strength and hardness properties. Moreover, the plasticity increases with increasing annealing temperature. Annealing at 700°C makes the material soften almost to the level of the initial cold-deformed state and significantly increases its plasticity.
The Multi-Purpose Detector (MPD) is constructing to study the properties of the hot and dense matter created in heavy-ion collisions in the energy range of 4-11 A*GeV where the maximum baryonic ...density is expected. The crucial detector in the new experimental setup is a large-sized barrel electromagnetic calorimeter (ECal), designed for precise spatial and energy measurements for photons and electrons. Taking into account the requirements of high energy resolution, dense active medium with the small Moliere radius, and high segmentation of ECal, the Shashlyk-type electromagnetic calorimeter with projective geometry has been selected. The mass production of ECal modules has been started. In this talk, we report about methods and technologies for the quality control of ECal modules and their components.
Financial policy of any entity comes down to managing economic parameters and relies on exploration of the strength of relations and dependencies between them. By means of analysis of the given ...indicators and identification of the degree of their correlation with the basic indicators, financial engineers get vast opportunities concerning economic processes modeling and optimization. Thus, in the sector of commercial credit, which is characterized by the absence of complete Russian procedures that would help assess the risk of the creditor, the study of credit analysis exhibitors system provides the key to the development of modern models and methodological assessment technologies. The present scientific work includes theoretical, methodological, analytical and financial engineering components. The theoretical part has to provide the theoretical basis for the research, reflect the terms and definitions overview and show the development of the basic complex concept – algorithmic modeling of commercial debtor segmentation. The methodological component is devoted to the study of the fundamental principles which help construct the system of analytical indicators and establish their connection with the algorithmic model. The analytical and financial-engineering component of the scientific work which is of fundamental importance (as it reflects the implementation of the research focus), consists of five stages: 1) identification and thematic grouping of the creditor's risk indicators; 2) indicators unification in the form of the commercial debtor segmentation algorithm; 3) algorithmic model testing and performance evaluation; 4) explanation of cause-effect relationships strength between the interpenetrating exponents of the algorithmic model; 5) identification of the most valuable parameters (identifying factors) of credit analysis in the commercial lending sector. Studies were carried out using selected materials taken from Kemerovo Region agricultural companies. Thus, the result of the research is the author's debtor segmentation. The model makes it possible to form risk groups in the commercial lending sector. The analytical structure is based on the combination of key credit risk parameters taking regional and industry specific features of businesses operation into account and justified by strong correlation of the algorithm elements. That helps financial analysts save time and have equivalent effect of credit risk assessment procedure.
The effect of cold rolling to 80% thickness reduction and annealing at 973–1373 K for 1 h on the microstructure and mechanical properties of a C-containing CoCrFeNiMn high-entropy alloy was studied. ...Cold rolling significantly strengthened the alloy to the yield strength of 1310 MPa. Annealing at 973 K or 1073 K resulted in incomplete recrystallization of an fcc matrix and M23C6-type carbide precipitations aligned with highly elongated grains/subgrains. Complete recrystallization occurred during annealing at 1173 − 1373 K. The ordered arrangement of the carbides was not observed after annealing at 1273 K or 1373 K. The volume fraction of carbides decreased with increasing the annealing temperature that can be reasonably described by a Thermo-Calc prediction. The coarsening behavior of the microstructure constituents was studied during isothermal annealing at 1173 K for 1–50 h. It was found that the grain growth and the particle coarsening can be expressed by power law functions of annealing time with grain/particle size exponents of about 2 and 3, respectively. An increase in the annealing temperature from 973 K to 1373 K led to a gradual softening of the alloy; the yield strength decreased from 870 MPa to 320 MPa, whereas total elongation increased from 24% to 47%, respectively. Contributions of various strengthening mechanisms into the overall strength of the alloy were discussed.
Microstructural evolution during cold sheet rolling to 80% thickness strain and annealing at 600–1100 °C for 30 min of the CoCrFeNiMn high entropy alloy doped with 1 at.% of C and resulting ...mechanical properties of the alloy are reported. It is shown that in the initial homogenized (24 h at 1000 °C) condition the alloy has single fcc phase structure. Cold rolling is accompanied by dislocation slip, deformation twinning and formation of shear bands. Annealing at 600 °C after 80% cold rolling results only in partial recrystallization of cold-deformed structure, while an increase of the annealing temperature produces fully recrystallized microstructure. Comparison with the data on undoped CoCrFeNiMn alloy demonstrates that the addition of carbon pronouncedly increases dislocation activity simultaneously retarding deformation twinning during rolling and decreases the fraction of twin boundaries in the annealed condition. The effect of carbon can be attributed to an increase of stacking fault energy of the carbon-containing alloy. Cold rolling results in a substantial strengthening of the alloy; its ultimate tensile strength approaches 1500 MPa, but at the expense of low ductility. Good combination of strength and ductility can be obtained after annealing. For example, after annealing at 800 °C, the alloy has yield strength of 720 MPa, ultimate tensile strength of 980 MPa, uniform elongation of 21% and elongation to fracture of 37%. It is shown that the high strength of the annealed alloy can be attributed to (i) strong grain boundary strengthening; (ii) solid solution strengthening by carbon.
•CoCrFeNiMn high entropy alloy doped with 1 at.% C was produced by vacuum arc melting.•After homogenization annealing at 1000 °C the alloy has single fcc phase structure.•The alloy was cold rolled to 80% thickness strain and annealed at 600–1100 °C.•After annealing at 800 °C the alloy combines high strength with good ductility.•High strength of the annealed alloy mainly is due to strong Hell-Petch strengthening.
A Radiation Transport Monitor Alferov, V. N.; Britvich, G. I.; Vasiliev, D. A. ...
Instruments and experimental techniques (New York),
07/2021, Letnik:
64, Številka:
4
Journal Article
Recenzirano
A radiation monitor based on a cast polystyrene scintillator with wavelength-shifting optical fibers is described, which has a large aperture; the dimensions of the active part of the detector are ...100 × 200 × 5 cm. The monitor also includes a sensor for the presence of a monitored object and a television camera, united by a single control system. The monitor is designed to control transportation of radioactive materials. The operating experience is described.
Multifaceted, multifactor and multicomponent nature of credit risk makes it possible to consider it as an integral hypothetical unit which consists of the autonomous diverse segments specifying risky ...situations. As the given article is focused on the mechanism of loan fund circulation within foreign currency loan the author considers the combination of credit, interest rate, foreign exchange and inflation risks within the aggregate (total, combined) credit risk. Foreign exchange and inflation risks generate special interest in relation to evaluation procedures as there can be statutory regulation of interest rate risk and well-functioning mechanism of debt capacity analysis as the main factor of credit risk. As commercial loans and bank credits taken by Russian companies are wide spread the authors of the article suggest an innovative procedure of aggregate credit risk assessment considering agricultural companies, as well as companies belonging to chemical and machine-building industries as “pure borrowers” (debtors). The research has a set sequence of procedures. During the first stage the authors structured a risky situation in the lending process, determined specific constituents and performed their further strategic agreement. The second stage implies the analysis of the possibilities and specific characteristics of the preliminary segment assessment of the risk level. The third stage involves the development of experimental synthetic approach to the segment assessment of the aggregate credit risk in case of foreign exchange rate and interest rate volatility when there are inflation expectations. The procedure considers the following scenarios: 1) isolated assessment of inflation risk; 2) isolated assessment of exchange rate risk; 3) complex assessment of inflation and exchange rate risks.
An improved Shashlyk calorimeter Atoian, G.S.; Britvich, G.I.; Chernichenko, S.K. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2008, Letnik:
584, Številka:
2
Journal Article
Recenzirano
Shashlyk electromagnetic calorimeter modules with an energy resolution of about
3
%
/
E
(
GeV
)
for
50
–
1000
MeV
photons have been developed, and a prototype tested. Details of these improved ...modules, including mechanical construction, selection of wave shifting fibers and photo-detectors, and development of a new scintillator with improved optical and mechanical properties are described. How the modules will perform in a large calorimeter was determined from prototype measurements. The experimentally determined characteristics of the calorimeter prototype show energy resolution of
σ
E
/
E
=
(
1.96
±
0.1
)
%
⊕
(
2.74
±
0.05
)
%
/
E
, time resolution of
σ
T
=
(
72
±
4
)
/
E
⊕
(
14
±
2
)
/
E
(
ps
)
, where photon energy
E is given in GeV units and
⊕
means a quadratic summation. A punch-through inefficiency of photon detection was measured to be
ε
≈
5
×
10
-
5
(
Θ
beam
>
5
mrad
)
.
Microstructure and mechanical properties of the Fe-Mn-Cr-Ni-Al system non-equiatomic high entropy alloys with a different Al content (x = 0–14 at.%) were studied in the present work. The ...Fe40Mn25Cr20Ni15 alloy was composed of the face-centered cubic (fcc) matrix phase with a small amount of coarse body-centered cubic (bcc) particles. Addition of a small amount of Al (x = 2–6) resulted in an increase in the fraction of the bcc phase to 26% and the formation of fine B2 precipitates within the bcc phase. At higher amounts of Al (x = 10 and x = 14) the microstructure consisted of coarse bcc matrix grains with the B2 precipitates inside. The alloys tend to become stronger with an increase in the Al content from 0 to 10 at.%; further increase in Al concentration did not influence strength considerably. The alloys exhibited pronounced softening with an increase in testing temperature from 25 to 400 °C–600 °C. Ductility of the alloys was high enough (>50%) at all temperatures. A quasi-binary Fe40Mn25Cr20Ni15-Al phase diagram was constructed using a ThermoCalc software and a TCHEA2 database; reasonable agreement between the experimental and predicted phase compositions of the alloys was obtained. It was suggested that an addition of the strong bcc-stabilizing and compound-forming Al to a bcc-prone Fe40Mn25Cr20Ni15 alloy is beneficial for the development of the alloys with the disordered bcc matrix and the embedded B2 precipitates having attractive mechanical properties.
•(Fe40Mn25Cr20Ni15)100-xAlx (x = 0–14 at.%) high entropy alloys were arc melted.•X = 0–6 alloys were mixtures of fcc and bcc phases.•X = 10–14 alloys had bcc matrix with B2 precipitates.•Reasonable agreement with ThermoCalc phase diagram was found.•Bcc/B2 alloys had high strength and ductility in compression at T ≤ 400 °C.
A new approach to increase the tensile performance of high entropy alloys (HEAs) by producing a duplex ultrafine-grained (UFG) structure was reported in this work. A novel HEA based on the CoCrFeNiMn ...system with substantial amounts of Al and C was used for the illustration of this approach. In the as-cast condition the alloy had almost entirely a single face-centered cubic (fcc) phase structure with an insignificant amount of M23C6 carbides. After cold rolling and annealing at 800–1000 °C an increased amount of fine second phases, namely M23C6 carbides and B2 phase, effectively pinned boundaries of recrystallized fcc grains. As a result, a duplex UFG structure composed of the recrystallized fcc grains and M23C6 and B2 particles was produced. The alloy with the UFG structure demonstrated attractive mechanical properties. For example, after annealing at 900 °C the alloy had the yield strength of 785 MPa, the ultimate tensile strength of 985 MPa, and elongation to fracture of 32%. The phase composition of the alloy in different conditions was compared with the equilibrium phase diagram obtained using a Thermo-Calc software. Strengthening mechanisms were qualitatively analyzed, and some possibilities for further improvement of strength of the alloy were discussed.
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