Dislocation-enhanced induced Snoek peak associated with heavy interstitials in the presence of kinks moving harmonically in anisotropic body-centered-cubic metals.

Abstract

The energy dissipation per cycle due to the motion of heavy interstitials in the presence of a harmonically oscillating rigid kink is investigated analytically as well as numerically in terms of discrete Fourier k\ensuremath{\rightarrow}-space transformation technique. In the linear-response case, a discrete Debye relaxation spectrum with three distinct branches is found to represent the inelastic behavior of the system uniquely and exactly. It has been observed by extensive computer modeling experiments that the induced Snoek peak is composed of three subpeaks---one acoustic (1) and two optical (modes 2 and 3) in character---which have the following peak-maximum intensity ratios, approximately: 11:9:2 for pure screw dislocation and 13:8:3 for 71\ifmmode^\circ\else\textdegree\fi{} nonscrew dislocation, respectively. The second most intense peak which is associated with the optical mode 2, occurs exactly at the ordinary Snoek peak position, and as far as the linewidth and the skewness parameter are concerned it resembles an ideal Debye peak.