Time-Dependent Internal Friction in Aluminum and Magnesium Single Crystals

Chambers, R.H.; Smoluchowski, R.

doi:10.1103/physrev.117.725

Cited by 73 publications

(15 citation statements)

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“…Upon increasing strain, the decrement has a tendency to level off, not exceeding ~5X10~2. Figure 1 also shows data from observations of damping at low amplitudes at 15 kc/sec on aluminum reported by Chambers and Smoluchowski,20 and results obtained at 40 kc/sec by Caswell 21 who used copper crystals. The figure shows that there is still a gap in data at strain amplitudes between 10~5 and 10~~4 which remains to be investigated.…”

Section: Amplitude Dependencementioning

confidence: 67%

Dislocation Damping in Macrosonic Fields

Langenecker

1966

Phys. Rev.

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The damping of high-amplitude ultrasonic waves (macrosound) in the 40 kc/sec range is observed in high-purity aluminum single crystals at room temperature and at strains above 10~4. At strain amplitudes between 10 -4 and 10~3, the decrement ranges from 1 to 3X10 -2 and levels off at ~5X10~2 for strains above 10~3. The dependence of decrement on irradiation time shows a rapid increase at the beginning of irradiation (a region), a somewhat reduced damping over a longer period of time (0 region), and another increase in damping before termination of the experiment (y region). The data lie by about two orders of magnitude above those from previous observations on internal friction to which the Granato-Lucke theory and associated concepts apply. The present experimental conditions are discussed from the viewpoint of a refined model which accounts for the irreversible changes in dislocation structures caused by macrosonic irradiation and revealed by transmission electron microscopy. Indications are given of points requiring further study.

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Section: Amplitude Dependencementioning

confidence: 67%

Dislocation Damping in Macrosonic Fields

Langenecker

1966

Phys. Rev.

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“…Chambers and Smoluchowski [8] observed variations of internal friction with excitation time and logarithmic relaxation (what is now termed slow dynamics) in zone-refined, well-annealed aluminum single crystal, as predicted by the Granato-Lücke model (zone-refining, also called zone melting, is a technique for the purification of a crystalline material in which a molten region travels through the material to be refined, picks up impurities at its advancing edge, and then allows the purified part to recrystallize at its opposite edge). Their work shows hysteresis in the decrement as a function of strain amplitude and a saturation effect during long periods of excitation (much like that observed in rock).…”

Section: Historical Contextmentioning

confidence: 99%

“…Decrement is defined as equal to the energy lost per cycle divided by twice the stored energy of the system (modified from [8]). The solid triangles are for data taken before longduration excitation, and the open triangles were taken after wave excitation for 20 min at a strain amplitude of 2.5~10 --6.…”

Section: Historical Contextmentioning

confidence: 99%

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Nonlinear Elasticity and Nondestructive Evaluation and Imaging

Guyer

Johnson

2009

Nonlinear Mesoscopic Elasticity

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Based on methods described in the previous chapters, we now turn to applications to nondestructive evaluation. In Section 13.1 we provide a general overview and perspective. Following this, Section 13.2 provides a historical overview of the development of the domain in metals, long before rocks and other materials were discovered to exhibit the same behaviors. In Section 13.3 a simple crack model based on work by a number of individuals, but primarily Igor Solodov, is described. Following this, we describe methods that are part of what we call nonlinear elastic wave spectroscopy (NEWS), Section 13.4. Contained in this group are modulation methods (Section 13.4.1), resonance methods (Section 13.4.5), signal ringdown methods (Section 13.4.6), and methods based on slow dynamics (Section 13.4.7). We then describe a number of measurements of progressive damage employing a number of NEWS methods in Section 13.5. Methods of localization and imaging follow in Section 13.6 based on harmonics (Section 13.6.1) and wave modulation (Section 13.6.2) and time reversal (Section 13.6.3). Before summarizing, two other methods of isolating the nonlinear response are described as well (Sections 13.7.1 and 13.7.2, respectively). OverviewOver the past decade or so in particular there have been many developments in the area of nondestructive evaluation. The area is relatively well developed; however, the quantitative relationship between elastic nonlinear response and mechanical (or other) damage is still an open area that requires significant attention. That said, discerning that damage is present and localizing it are well advanced. In what follows, we first provide a historical overview of nondestructive evaluation based on nonlinear elastic means. We then describe the relatively large number of diagnostic and imaging methods by example, linking the method to rigorous development in previous chapters. Following this we describe imaging methods.

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“…G. Alefeld (private communication, 1964) has suggested that the resulting increased pinning-point density at certain points on the dislocation would favor the emission of s orne of the pinning points back into the lattice, thus resulting in a net decrease in pinning points. Thus, some of the time effects resulting from high-amplitude oscillations in the bee tran,... sition metals may have the same origins as the time effects seen in fcc and hcpmetals (see Ref 51…”

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confidence: 99%