scholarly journals Effect of nanosecond unipolar electropulse effects on the properties of the alloy Cu-1% Cr. Part 2. Relation of alloy properties with Cr content in Cu lattice

2019 ◽  
Vol 57 (1) ◽  
pp. 127-135
Author(s):  
Igor E. Ignatiev ◽  
◽  
Pavel V. Kotenkov ◽  
Eduard Yu. Goyda ◽  
Elena V. Ignatieva ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
Thermal Conditions ◽  
Signal Duration ◽  
Electric Pulses ◽  
Time Treatment ◽  
Subsequent Decrease ◽  
Copper Melt ◽  
Mathematical Formulas ◽  
Secondary Precipitates ◽  
Alloy Properties

The effect of treatment of copper melt with chromium additives in the amount of 1% by weight is considered nanosecond unipolar electric pulses with a frequency of 1000 Hz, a single signal duration of one nanosecond and a power of 10 kW on the electrical resistivity and hardness of the resulting alloy. A study was made of the macro and microstructure of alloy samples created using electropulse effects and comparison samples obtained under the same thermal conditions, but without it. The samples were aged for 2 hours at 4500C. It has been found that electropulse treatment of the melt leads to an increase in hardness and decrease in the electrical resistance of the alloy as well as during aging, and the influence of this effect remains noticeable even after the aging process. Hardness and electrical resistance in all alloy samples are described mathematically as a function of chromium content in the copper lattice and in secondary precipitates. The role of nanosecond unipolar electroimpulsive effects on the Cu-1% Cr melt in improving the above characteristics of the resulting alloy compared with the thermo-time treatment without the electropulse effect is revealed. An explanation of the mechanism of the electropulse effect on the melt, leading to the separation of chromium atoms in the liquid state and the subsequent decrease in its solubility in the copper lattice, is proposed. The results of the study are presented in the form of drawings of macro- and microstructure of samples of the alloy Cu-1% Cr, tables, graphs and mathematical formulas. It was concluded that it is advisable to use a nanosecond unipolar electropulse effect with a frequency of 1000 Hz, a single signal duration of one nanosecond and a power of 10 kW per Cu-1% Cr melt to produce the corresponding alloy with improved hardness and electrical resistance.

scholarly journals Effect of nanosecond electropulse effects on the properties of the alloy Cu-1.75% Cr

2019 ◽  
Vol 58 (5) ◽  
pp. 133-140
Author(s):  
Igor E. Ignatiev ◽  
◽  
Pavel V. Kotenkov ◽  
Elena V. Ignatieva ◽  
Eduard Yu. Goyda ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
Electric Pulse ◽  
Melt Processing ◽  
Electric Pulses ◽  
Proposed Model ◽  
Significant Difference ◽  
Electrical Pulses ◽  
Mathematical Formulas ◽  
Cr System

The hardness, electrical resistance, deformation resistance of the Cu-1.75%Cr alloy obtained by irradiating its melt at a temperature of one thousand three hundred and fifty degrees Celsius by nanosecond unipolar electrical pulses of one thousand Hertz, a single signal duration of one nanosecond and ten kilowatts were experimentally determined. The dependences of the determined properties of the metal on the duration of the electric pulse irradiation are established. A comparison was made between irradiated and unirradiated, but obtained under the same thermal and temporal conditions, alloy samples. An improvement was observed in both mechanical (increase in hardness up to eight percent) and electrical (decrease in electrical resistance to fourteen and a half percent) characteristics due to electric pulse effect on the melt. It was found that the best time for electropulse treatment is from five to ten minutes. It is shown that the effect of irradiation of the Cu-1.75%Cr melt on the electrical resistance of the resulting alloy and its hardness differs from the results of irradiation of the Cu-1%Cr melt, but retains the same tendencies in changing properties. A significant difference was found in the hardness values of unirradiated samples of Cu-1.75%Cr and Cu-1%Cr alloys. A model of the connection of electrical resistance and hardness of Cu-Cr alloys with the redistribution of chromium in their volume is proposed. The results of melt processing by nanosecond unipolar electric pulses are presented in the form of microstructure snapshots, tables, and mathematical formulas. On the basis of the obtained results, it was concluded that the proposed model is useful for assessing the quality of Cu-Cr system alloys from the standpoint of increasing their hardness and decreasing electrical resistance, including after electropulse treatment of the corresponding melts.

scholarly journals Effect of the Electron Beam on the Alloy Properties of Polymethyl Methacrylate and Cycloolefin Copolymer

2021 ◽  
Author(s):  
Maryam Khosravinezhad ◽  
Masoumeh Kazemi
Keyword(s):  
Electron Beam ◽  
Thermal Properties ◽  
Polymethyl Methacrylate ◽  
Electrical Resistance ◽  
Moisture Absorption ◽  
Mechanical Test ◽  
Impact Resistance ◽  
Mechanical And Thermal Properties ◽  
Optimal Sample ◽  
Alloy Properties

Polymethyl methacrylate (PMMA) is a transparent thermoplastic with excellent optical properties, transparent surface, low moisture absorption, tensile and electrical resistance. In this study, the alloy was prepared through PMMA and cycloolefin copolymer (COC) due to some similar properties. The mechanical test showed that properties such as impact resistance, elongation, tensile, and flexural strength decreased by adding COC by up to 20% due to less incompatibility and miscibility, but mentioned properties improved by adding COC 40% due to sub-phase generation. The DSC and DMTA tests showed improvement in the thermal properties of alloys by adding 40% COC. SEM micrographs exhibited a softer surface and more phase elongation of the alloy. Finally, the sample was selected as the optimal sample in terms of mechanical properties irradiated by electron beam, and amplification results showed that a dose of 50 KGY increased the mechanical and thermal properties relatively.

Analysis of 2D and 3D defects associated with precipitation of Cu in silicon

1991 ◽  
Vol 49 ◽  
pp. 870-871
Author(s):  
P.M. Rice ◽  
MJ. Kim ◽  
R.W. Carpenter
Keyword(s):  
Colony Growth ◽  
Dark Field ◽  
Dark Side ◽  
Silicide Phase ◽  
Strain Fields ◽  
Near Surface ◽  
Unknown Composition ◽  
Secondary Precipitates ◽  
20 Nm ◽  
2D And 3D

Extrinsic gettering of Cu on near-surface dislocations in Si has been the topic of recent investigation. It was shown that the Cu precipitated hetergeneously on dislocations as Cu silicide along with voids, and also with a secondary planar precipitate of unknown composition. Here we report the results of investigations of the sense of the strain fields about the large (~100 nm) silicide precipitates, and further analysis of the small (~10-20 nm) planar precipitates.Numerous dark field images were analyzed in accordance with Ashby and Brown's criteria for determining the sense of the strain fields about precipitates. While the situation is complicated by the presence of dislocations and secondary precipitates, micrographs like those shown in Fig. 1(a) and 1(b) tend to show anomalously wide strain fields with the dark side on the side of negative g, indicating the strain fields about the silicide precipitates are vacancy in nature. This is in conflict with information reported on the η'' phase (the Cu silicide phase presumed to precipitate within the bulk) whose interstitial strain field is considered responsible for the interstitial Si atoms which cause the bounding dislocation to expand during star colony growth.

The Application of Laboratory Formulas to Clinical Voice Management

1995 ◽  
Vol 4 (2) ◽  
pp. 62-69 ◽  
Author(s):  
Katherine Verdolini ◽  
Ingo R. Titze
Keyword(s):  
Fundamental Frequency ◽  
Voice Disorders ◽  
Clinical Interventions ◽  
Case Examples ◽  
Interactive Nature ◽  
Mathematical Formulas

In this paper, we discuss the application of mathematical formulas to guide the development of clinical interventions in voice disorders. Discussion of case examples includes fundamental frequency and intensity deviations, pitch and loudness abnormalities, laryngeal hyperand hypoadduction, and phonatory effort. The paper illustrates the interactive nature of theoretical and applied work in vocology

Sequential Treatment of Deep Leg Vein Thrombosis with Porcine Plasmin and Low Dose Streptokinase

1982 ◽  
Vol 48 (02) ◽  
pp. 190-195 ◽  
Author(s):  
G A Marbet ◽  
R Eichlisberger ◽  
F Duckert ◽  
M A de Silva ◽  
L Biland ◽  
...  
Keyword(s):  
Low Dose ◽  
Significant Negative Correlation ◽  
Sequential Treatment ◽  
Factor V ◽  
Complete Dissolution ◽  
Vein Thrombosis ◽  
Time Treatment ◽  
Lysis Time ◽  
Euglobulin Lysis Time ◽  
Thrombolytic Effect

SummarySequential treatment of deep leg vein thrombosis with porcine plasmin and low dose streptokinase (10,000-20,000 U/h) produces strong systemic fibrinolysis as demonstrated by the sustained decrease of euglobulin lysis time, of thromboplastin time values in percent, fibrinogen and factor V levels. There is a statistically significant negative correlation between thrombolytic results and euglobulin lysis time. Treatment periods below 3 days are unlikely to give satisfactory results. Occluded vein segments with an apparent median age of 4 days including thrombi older than 10 days (20% of cases) are cleared with an average chance of 50%. Complete dissolution of all thrombi proximal to the crural veins has been demonstrated in 47/114 = 41.2%, some thrombolytic effect in 31/114 = 27.2% and treatment failure in 36/114 = 31.6%. The data favour laboratory monitoring of thrombolytic therapy.

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