Kv. Sapozhnikov et al., INFLUENCE OF IMPURITY CONTENT ON THE ACOUSTOPLASTIC EFFECT, INTERNAL-FRICTION, AND YOUNGS MODULUS DEFECT DURING DEFORMATION OF CU-NI SINGLE-CRYSTALS, Philosophical magazine. A. Physics of condensed matter. Structure, defects and mechanical properties, 77(1), 1998, pp. 151-166
Oscillatory stress amplitude dependences of the acoustoplastic effect,
absorption of ultrasonic vibrations (frequency of about 100 kHz) caus
ing this effect, and Young's modulus defect were simultaneously measur
ed in situ during quasistatic deformation of Cu-1.3-7.6 at.% Ni single
crystals. The time dependences of the magnitude of the acoustoplastic
effect at constant oscillatory stress amplitudes were also obtained.
The amplitude-dependent internal friction and Young's modulus defect d
iminish drastically with increasing Ni content. The dependence of the
magnitude of the acoustoplastic effect on the Ni concentration is much
less pronounced and is reversed with increase in oscillatory stress a
mplitude. Data on the kinetics of the acoustoplastic effect revealed '
instant' (time-independent) and 'relaxational' (time-dependent) compon
ents. Both components show a similar dependence on Ni concentration, t
hus indicating their common origin. It is concluded that, while the am
plitude-dependent internal friction is largely due to dislocation-poin
t-defect interactions, the acoustoplastic effect originates mainly fro
m dislocation-dislocation interactions.