Dislocation damping in metals

Niblett, Daniel; Wilks, J.

doi:10.1080/00018736000101159

Cited by 186 publications

(29 citation statements)

References 97 publications

(66 reference statements)

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“…The peak temperature too is influenced by the annealing process. The present results indicate that annealing moves the Bordoni peak to a lower temperature thus confirming the findings of Niblett and Wilks [3] and Okuda [21]. Bruner and Mecs [23] and Okuda [21], however, showed that the Bordoni peak moves to higher temperatures during low temperature annealing.…”

Section: Figuresupporting

confidence: 91%

Effect of isothermal annealing on the Bordoni relaxation in cold worked copper

Siddiqui

Alp

1991

J Mater Sci

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The Bordoni relaxation in ultra-purity cold worked copper subsequent to isothermal annealing in the temperature range 298-423 K at 700 Hz frequency is investigated using a set up based on the electrostatic system. The Bordoni peak is observed at 79 ___ 2 K. The annealing characteristics of the Bordoni peak are found to be of complex nature. The decay and subsequent regrowth of the peak following annealing above room temperature are interpreted in terms of defects diffusing to dislocations and their removal from dislocations, respectively. The calculated activation energy values for the first decrease (0.55 eV), first increase (0.24 eV) and first minimum (0.27 eV) are in good agreement with the activation energies for interstitial and di: vacancy diffusion estimated by different workers. The activation energy for divacancy diffusion is computed to be 0.49 eV.

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Section: Figuresupporting

confidence: 91%

Effect of isothermal annealing on the Bordoni relaxation in cold worked copper

Siddiqui

Alp

1991

J Mater Sci

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“…Therefore, the functional dependence of damping on the peak specimen stress (as reported) may not be synonymous with the dependence of the local damping on the-local stress. Mason [8,9] is one of several researchers [10,11,12] who reported a similar increase in damping ratio with increasing stress for aluminum. It is difficult to determine from these earlier works whether natural frequencies of vibration were above or below the Zener relaxation frequency.…”

Section: T3 Aluminummentioning

confidence: 84%

Material Damping in Aluminum and Metal Matrix Composites

Crawley

Schoor

1987

Journal of Composite Materials

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The material damping in beam-like specimens of aluminum and metal matrix composites was measured. A unique apparatus to determine damping by free decay while the specimens are in free fall in a vacuum was used. The specimens tested include 2024-T3 and 6061-T4 aluminum, and unidirectional graphite/metal matrix specimens with P55 and P100 fibers and 6061 Aluminum and AZ91C Magnesium as matrix materials. Tests were conducted to determine the dependence of damping on frequency and stress level. For the aluminum specimens, the material damping followed the Zener model at very low stress levels. Below the Zener relaxation frequency, a strong dependence of damping on stress was found for even moderate stress levels. Damping for the aluminum matrix materials was slightly above that predicted by the Zener model for a homogeneous bar of the matrix aluminum. For the magnesium matrix specimens, damping significantly above the Zener prediction for the homogeneous matrix material was observed.

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“…17,21,23,24) Measurements were performed in a mechanical spectrometer based on an inverted torsion pendulum under Ar at atmospheric pressure. The maximum strain on the sample surface was 5 × 10 .…”

Section: Methodsmentioning

confidence: 99%

Mobility of Twin Boundaries in Fe-Pd-Based Ferromagnetic Shape Memory Alloys

et al. 2016

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The mobility of twin boundaries in (at.%) Fe 70 Pd 30 , Fe 67 Pd 30 Co 3 and Fe 66.8 Pd 30.7 Mn 2.5 has been studied by mechanical spectroscopy. Measurements were carried out in amplitude dependent damping regime. A new model based on the Friedel theory was developed to obtain the activation energy ( 2 kJ/mol) for twin boundaries motion. The model describes the amplitude dependent damping from thermally assisted break-away of dislocations. Interaction processes among twin boundaries, dislocations and vacancies during the recovery of the structure are also discussed. Moreover, a damping peak related to a dislocation dragging mechanism controlled by vacancies migration without break-away, earlier reported in Fe-Pd alloys, was also found in Fe-Pd-Co and Fe-Pd-Mn alloys.

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Dislocation damping in metals

Cited by 186 publications

References 97 publications

Effect of isothermal annealing on the Bordoni relaxation in cold worked copper

Effect of isothermal annealing on the Bordoni relaxation in cold worked copper

Material Damping in Aluminum and Metal Matrix Composites

Mobility of Twin Boundaries in Fe-Pd-Based Ferromagnetic Shape Memory Alloys

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