Effects of cyclic stress on the creep behaviour and dislocation microstructure of pure copper in the temperature range 0.4 to 0.5T m

1988 ◽  
Vol 23 (6) ◽  
pp. 2051-2058 ◽  
Author(s):  
Jae Kon Lee ◽  
Soo Woo Nam
Keyword(s):  
Creep Behaviour ◽  
Pure Copper ◽  
Cyclic Stress ◽  
Temperature Range

An anomaly in the specific heat below 3 °K of copper containing hydrogen

1969 ◽  
Vol 47 (14) ◽  
pp. 1485-1491 ◽  
Author(s):  
Neil Waterhouse
Keyword(s):  
Specific Heat ◽  
Molecular Hydrogen ◽  
Pure Copper ◽  
Solid Hydrogen ◽  
Rotational State ◽  
Experimental Results ◽  
Ortho Hydrogen ◽  
Temperature Range ◽  
A Value ◽  
Heat Curve

The specific heat of copper heated in hydrogen at 1040 °C has been measured over the temperature range 0.4 to 3.0 °K and found to be anomalous. The anomaly occurs in the same temperature range as the solid hydrogen λ anomaly which, in conjunction with evidence of ortho to para conversion of hydrogen in the sample, suggests the presence of molecular hydrogen in the copper. The anomaly reported by Martin for "as-received" American Smelting and Refining Company (ASARCO) 99.999+ % pure copper has been briefly compared with the present results. The form of the anomaly produced by the copper-hydrogen specimen has been compared with Schottky curves using the simplest possible model, that for two level splitting of the degenerate J = 1 rotational state of the ortho-hydrogen molecule.Maintenance of the copper-hydrogen sample at ~20 °K for approximately 1 week removed the "hump" in the specific heat curve. An equation of the form Cp = γT + (464.34/(θ0c)3)T3 was found to fit these experimental results and produced a value for γ which had increased over that for vacuumannealed pure copper by ~2%.

Effect of cyclic stress reduction on the creep behaviour of Al-40wt%Zn alloy

2007 ◽  
Vol 388 (1-2) ◽  
pp. 219-225 ◽  
Author(s):  
F. Abd El-Salam ◽  
A.M. Abd El-Khalek ◽  
R.H. Nada
Keyword(s):  
Stress Reduction ◽  
Creep Behaviour ◽  
Cyclic Stress ◽  
Zn Alloy

Towards a Correlation between High-Temperature Creep and Volume Diffusion for Equiatomic NiTi Alloys

2008 ◽  
Vol 280-281 ◽  
pp. 97-104
Author(s):  
Virginie Taillebot ◽  
S. Divinsky ◽  
Christian Lexcellent ◽  
Jean Bernardini ◽  
Dezső L. Beke
Keyword(s):  
Diffusion Coefficient ◽  
High Temperature ◽  
Master Curve ◽  
Volume Diffusion ◽  
Creep Behaviour ◽  
High Temperature Creep ◽  
Temperature Range ◽  
Creep Measurements ◽  
Effective Choice ◽  
Stationary Creep

Classically a master curve as Dorn's equation is applied for elucidating stationary creep behaviour within high temperature range (T > 0.6 Tm). As the diffusion of both 63Ni and 44Ti have been measured in an equiatomic NiTi, an effective choice of creep-relevant diffusion coefficient D may be possible. Moreover, creep measurements in the same temperature range performed can be found in the literature. The correlation does not permit to establish precisely what D coefficient to integrate in the Dorn's equation.

TRANSPORT PROPERTIES OF PURE METALS AT HIGH TEMPERATURES: I. COPPER

1967 ◽  
Vol 45 (11) ◽  
pp. 3677-3696 ◽  
Author(s):  
M. J. Laubitz
Keyword(s):  
High Temperature ◽  
Transport Properties ◽  
High Temperatures ◽  
Pure Copper ◽  
High Temperature Properties ◽  
Temperature Range ◽  
Pure Metals

This paper is the first of a series reporting our investigations into the high-temperature properties of the monovalent metals. It contains a description of the methods used in these investigations, and the results of measurements of the transport properties of pure copper, over the temperature range 300–1 250 °K. These results are compared with some previously published work, and also with standard theoretical expressions applicable to the monovalent metals.

Interface Controlled Diffusional Creep of Cu + 2.8 at.% Co Solid Solution

2012 ◽  
Vol 322 ◽  
pp. 33-39 ◽  
Author(s):  
Sergei Zhevnenko ◽  
Eugene Gershman
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Surface Tension ◽  
High Temperature ◽  
Creep Behavior ◽  
Pure Copper ◽  
Diffusional Creep ◽  
High Temperature Creep ◽  
Temperature Range ◽  
Different Temperatures

High-temperature creep experiments were performed on a Cu-2.8 ат.% Co solid solution. Cylindrical foils of 18 micrometers thickness were used for this purpose. Creep tests were performed in a hydrogen atmosphere in the temperature range of about from 1233 K to 1343 K and at stresses lower than 0.25 MPa. For comparison, a foil of pure copper and Cu-20 at.% Ni solid solution were investigated on high temperature creep. Measurements on the Cu foil showed classical diffusional creep behavior. The activation energy of creep was defined and turned out to be equal 203 kJ/mol, which is close to the activation energy of bulk self-diffusion of copper. There was a significant increase in activation energy for the Cu-20 at.% Ni solid solution. Its activation energy was about 273 kJ/mol. The creep behavior of Cu-Co solid solution was more complicated. There were two stages of diffusional creep at different temperatures. The extremely large activation energy (about 480 kJ/mol) was determined at relatively low temperature and a small activation energy (about 105 kJ/mol) was found at high temperatures. The creep rate of Cu-Co solid solution was lower than that of pure copper at all temperatures. In addition, the free surface tension of Cu-2.8 ат.% Co was measured at different temperatures from 1242 K to 1352 K. The surface tension increases in this temperature range from 1.6 N/m to 1.75 N/m. There were no features on the temperature dependence of the surface tension.

On The Mechanism of Interstitial Cluster Migration in α -FE

1998 ◽  
Vol 540 ◽  
Author(s):  
A.V. Barashev ◽  
Yu.N. Osetsky ◽  
D.J. Bacon
Keyword(s):  
Molecular Dynamics ◽  
Computer Simulations ◽  
Microstructure Evolution ◽  
Pure Copper ◽  
Simple Relationship ◽  
Statistical Accuracy ◽  
Jump Frequency ◽  
Temperature Range ◽  
Thermally Activated ◽  
Centre Of Gravity

AbstractRecent molecular dynamics (MD) computer simulations have shown that clusters consisting of up to a few tens of self-interstitial atoms (SIAs) are highly mobile along closed-packed crystallographic directions in pure copper and iron. This effect has important consequences for microstructure evolution in irradiated metals and so it is desirable to investigate the mechanisms of the cluster motion. In the present paper the results of MD modelling of the thermally-activated motion of clusters of 3, 9 and 17 SIAs in α-Fe in the temperature range from 90 to 1400 K are analyzed. The extensive MD data has enabled the migration of clusters, as well as that of individual SIAs in the clusters, to be treated with high statistical accuracy. The correlation between the motion of the centre of gravity of a cluster and the jumps of individual SIAs in the cluster is revealed. It is found that the SIAs in a cluster jump almost independently and their jump frequency depends on the number of SIAs in the cluster. This leads to a simple relationship between the jump frequency of a cluster and the number of SIAs in it. The cluster jump frequency exhibits a deviation from the Arrhenius relationship. The reason for this is discussed.

Solubility of Nitrogen Gas into Molten Copper at Temperature Range of 1,993 K to 2,443 K

2017 ◽  
Vol 36 (10) ◽  
pp. 1035-1038 ◽  
Author(s):  
Abdul Muizz Mohd Noor ◽  
Nik Hisyamudin Muhd Nor ◽  
Seiji Yokoyama
Keyword(s):  
Gibbs Energy ◽  
Pure Copper ◽  
Thermodynamic Temperature ◽  
Molten Copper ◽  
Nitrogen Gas ◽  
Levitation Melting ◽  
Temperature Range

AbstractSolubility of nitrogen gas into pure copper at temperature range of 1,993–2,443 K was studied with using a levitation melting apparatus. The solubility which was dissolved content of nitrogen equilibrated with nitrogen gas with a pressure of 101.3 kPa increased with the temperature of molten copper. However, the solubility was approximately 1.5 mass ppm even at 2,443 K. Absorption of nitrogen gas into pure copper obeyed the Sieverts’ law and was expressed as: $${1 \over 2}{{\rm{N}}_2}\left({{\rm{gas}}} \right) = \underline {\rm N} $$Here, the underlined element was expressed as the element dissolved into a molten copper. The relation between this reaction Gibbs energy, ${\Delta _{\rm{r}}}{G^0}$ [J], and thermodynamic temperature of the molten copper, T [K], was given as: $${\Delta _{\rm{r}}}{G^0} = 61573 + 48.75T$$

Creep Behaviour of AE42 Magnesium Alloy and its Composites Using Impression Creep Technique

2010 ◽  
Vol 638-642 ◽  
pp. 1552-1557 ◽  
Author(s):  
A.K. Mondal ◽  
Subodh Kumar
Keyword(s):  
Magnesium Alloy ◽  
Creep Rate ◽  
Hybrid Composites ◽  
Creep Behaviour ◽  
Longitudinal Direction ◽  
Impression Creep ◽  
Temperature Range ◽  
Sic Particles ◽  
Short Fibres ◽  
Stress Levels

The creep behaviour of a creep-resistant AE42 magnesium alloy has been examined in the temperature range of 150 to 240°C at the stress levels ranging from 40 to 120 MPa using impression creep technique. A normal creep behaviour, i.e., strain rate decreasing with strain and then reaching a steady state, is observed at all the temperatures and stresses employed. The stress exponent varies from 5.1 to 5.7 and the apparent activation energy varies from 130 to 140 kJ/mol, which suggests the high temperature climb of dislocation controlled by lattice self-diffusion being the dominant creep mechanism in the stress and temperature range employed. The creep behaviour of the AE42 alloy has also been compared with its composites reinforced with Saffil short fibres and SiC particles in four combinations. All the composites exhibited a lower creep rate than the monolithic AE42 alloy tested at the same temperature and stress levels and the decrease in creep rate was greater in the longitudinal direction than in the transverse direction, as expected. All the hybrid composites, i.e., the composites reinforced with a combination of Saffil short fibres and SiC particles, exhibited creep rates comparable to the composite reinforced with 20% Saffil short fibres alone at all the temperature and stress levels employed, which is beneficial from the commercial point of view.

Mocvd of Copper from the Solution of New and Liquid Precursor (hfac)Cu(1-pentene)

1998 ◽  
Vol 514 ◽  
Author(s):  
H.-K. Shin ◽  
Y.-H. Cho ◽  
D.-J. Yoo ◽  
H.-J. Shin ◽  
E.-S. Lee
Keyword(s):  
Surface Morphology ◽  
Deposition Rate ◽  
Deposition Temperature ◽  
Pure Copper ◽  
Copper Films ◽  
Vapor Pressures ◽  
Dynamic Vacuum ◽  
Liquid Precursor ◽  
Temperature Range

ABSTRACTIn an attempt to increase the deposition rate, new Cu (I) compounds, (hfac)Cu(1-pentene)(1) and (hfac)Cu(VTMOS)(2) have been synthesized. These species are chartreuse liquids and exhibit sufficient vapor pressures to allow high transport rates.In order to avoid the premature decomposition of the copper precursors during CVD processes, the 50% of free 1-pentene, and VTMOS was added to the compounds 1 and 2 respectively. These mixtures 1 and 2 were used in this study. Approximately 2gm of precursor was used for each experiment. No premature decomposition of the precursor in the source reservoir was observed during CVD processes. It is a sufficiently important result to expect the use of these mixtures in copper CVD to achieve the reproducible deposition.The copper films using these mixtures were deposited in a hot-wall pyrex reactor at a pressure of approximately 10–2 torr under dynamic vacuum. The films deposited at 100°C, 150°C and 200°C from the mixture 1. Pure copper films were deposited from these species. The resistivities 1.8 ∼ 2.1 μΩcm were obtained in the deposition temperature range. SEM revealed that the surface morphology of the films grown in these depositon temperature range was composed of dense film and grains were well connected. The deposition rate at 200°C was 3,500 Å/min.

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