The elastic properties of copper have been compiled and reviewed. Polycrystalline elastic constants included are: Young's modulus, the shear modulus, the bulk modulus, and Poisson's ratio. Single‐crystal constants of second‐, third‐, and fourth‐order are included. Over 200 references to the experimental literature are given. A few theoretical numbers are included. When sufficient data exist, best values are recommended together with their standard errors. Effects on the elastic constants of temperature, pressure, and mechanical (plastic) deformation are included. The Cauchy (central‐force) relationships and the single‐crystal—polycrystal relationship are also discussed.

Elastic Properties of Metals and Alloys. II. Copper

A review of the present state of understanding of the defect reactions occurring during the annealing of irradiated metals is given. These reactions are presently understood best for recovery stage 1. In this stage-aside from close pair recovery-freely migrating interstitials react with vacancies, other interstitials and impurity traps. Stage II annealing involves primarily the rearrangement of the interstitial clusters nucleated in stage I. Growth of larger clusters is obtained at the expense of smaller ones. In addition, in samples where extensive trapping of interstitials at impurities has occurred in stage I, detrapping of the interstitials from these impurities is observed in stage II. For a number of metals there is now clear evidence that single vacancies become mobile in stage III and annihilate at the interstitial clusters remaining from lower temperatures.

https://iopscience.iop.org/article/10.1088/0305-4608/3/2/005/pdf

Recovery of irradiated and quenched metals

An inexpensive apparatus for the continuous and automatic measurement of internal friction and elastic modulus is described. This apparatus is regenerative, maintaining a specimen in resonance at constant amplitude, unless interrupted by the experimenter. A vital component of this system, generally absent in such devices, is a phase‐locked loop.

Automatic internal friction and modulus measurement apparatus utilizing a phase‐locked loop

A study by internal friction measurements has been made on high‐purity copper of the effects of 1‐MeV electron irradiation on the rate of addition of point defects to dislocations in the temperature range 78–400°K. A distinct minimum in the point‐defect pinning rate is observed at about 160°K. It is also observed that a peak in the decrement as a function of irradiation time occurs, having a peak‐position time dependence which reflects the rate at which point defects arrive at dislocations. The above observations are discussed and taken as directed experimental evidence in support of the thermal‐conversion model. The maximum in internal friction and the minimum in the pinning rate are accounted for in a model of damping due to the dragging of point defects by dislocations.

/pdf/thermal-conversion-of-interstitials-in-electron-irradiated-307zrhui0p.pdf

Thermal conversion of interstitials in electron irradiated copper.

The internal friction and dynamic modulus of Mo polycrystals were measured after fast neutron irradiation at liquid helium temperature. Similar measurements were also made on a Mo single crystal and Cu polycrystals for comparison purpose. It is found that the dislocation pinning in Mo started at about 30°K. This pinning process proceeded up to 80°K. During annealing above 80°K, the modulus change along with the change in the α-peak was observed. The apparent difference between Mo and Cu in the pinning process is a continuous decrease in the thermal component of dislocation motion over a wider range of temperature in Mo.



Es wurde die innere Reibung und der Elastizitatsmodul von Mo-Polykristallen nach Bestrashlung mit schnellen Neutronen bei Heliumtemperatur untersucht. Zum Vergleich wurden ahnliche Messungen auch an einem Mo-Einkristall und an Cu-Polykristallen durch-gefuhrt. Es wird gefunden, das die Verankerung der Versetzungen in Mo bei etwa 30°K beginnt und sich bis zu 80°K erstreckt. Wahrend der Temperung oberhalb 80°K wurde eine Modulanderung zusammen mit der anderung des α-Maximums beobachtet. Der scheinbare Unterschied im Verankerungsprozes zwischen Mo und Cu besteht in einer kontinuierlichen Abnahme der thermischen Komponente der Versetzungswanderung uber einen groseren Temperaturbereich in Mo.

Dislocation pinning in Mo and Cu after neutron irradiation at low temperature

/pdf/new-mechanism-for-internal-friction-u9h06vwdqi.pdf

New Mechanism for Internal Friction

A study by internal friction and Young's modulus measurements has been made on high‐purity polycrystalline aluminum of the effects on dislocation damping by 1‐MeV electron irradiation in the temperature range 78–360 °K. These measurements confirm the presence of an internal friction ``peaking'' effect in aluminum in agreement with the defect dragging model proposed by Simpson and Sosin. In particular it is observed that during electron irradiation and for specific mechanical and thermal histories of the sample, the logarithmic decrement δ increases and later decreases. The increase is found to be generally strain amplitude independent and to be highly structure dependent, disappearing after a suitable high‐temperature anneal. Simultaneous modulus measurements show little or no effect due to electron irradiation between 78 and 240 °K, but the modulus increases monotonically for irradiations above 240 °K. The corresponding point‐defect kinetics exhibit a complex annealing behavior.

A. Sosin

Papers

New Mechanism for Internal Friction

Thermal conversion of interstitials in electron irradiated copper.

Defect dragging contribution to dislocation damping in electron-irradiated high-purity polycrystalline aluminum