| Autor: |
Sapozhnikov, K. V., Kustov, S. B. |
| Zdroj: |
Philosophical Magazine A; December 1997, Vol. 76 Issue: 6 p1153-1168, 16p |
| Abstrakt: |
Oscillatory strain amplitude dependences of the acoustoplastic effect and absorption of ultrasonic vibrations (frequency of about 100 kHz) causing this effect were measured in a wide temperature range in situ during quasistatic deformation of NaCl and Al single crystals. An increase in efficiency of the ultrasonic effect on the plastic deformation process has been found with an increase in temperature. The data obtained provide evidence for the distinction in basic mechanisms of the acoustoplastic effect and amplitude-dependent internal friction. The absorbtion of ultrasound is largely due to dislocation-point-defect interactions under reversible movement of mobile dislocations. Mechanical activation of irreversible movement of the same mobile dislocations through long-range internal stress fields of other dislocations and dislocation pileups is suggested as the basic mechanism of the acoustoplastic effect. Mechanisms are discussed determining the temperature dependences of the acoustoplastic effect, amplitude-dependent internal friction and type of amplitude hysteresis of the internal friction. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
