Internal Friction by Pinned Dislocations: Theory of the Bordoni Peak

The two most prominent internal friction peaks in cold worked metals at low temperature are shown to be related manifestations of the same nucleation mechanism of kink-antikink pairs in pinned dislocation segments depending, respectively, on the absence (Bordoni peak) or the presence (Niblett-Wilks peak) of geometrical kinks (antikinks). Correspondingly, diffusion of the nucleated thermal pairs accounts for the observed background internal friction. Peak and background components are both computed analytically and compared with experimental data.