Kv. Sapozhnikov et Sb. Kustov, ACOUSTOPLASTIC EFFECT AND INTERNAL-FRICTION OF ALUMINUM SINGLE-CRYSTALS IN VARIOUS DEFORMATION STAGES, Physics of the solid state, 39(10), 1997, pp. 1601-1606
The dependences of the acoustoplastic effect and the internal friction
on the oscillatory strain amplitude are measured in various deformati
on stages of low-purity aluminum single crystals. It is discovered tha
t the acoustoplastic effect is observed not only in the macroscopic pl
astic region of the stress-strain diagram, but also for microplastic d
eformation in the ''elastic'' loading and unloading stages. The sign o
f the effect reverses during unloading. An increase in the strain rate
leads to enhancement of the acoustoplastic effect and the absorption
of the energy of ultrasonic vibrations causing this effect with a freq
uency of about 100 kHz. It is concluded that the acoustoplastic effect
observed during both macro-and microplastic deformation is caused by
the irreversible high-speed motion of dislocations through the long-ra
nge stress field of the other dislocations after breaking through the
Cottrell atmospheres. (C) 1997 American Institute of Physics.