INFLUENCE OF TEMPERATURE AND STRAIN ON THE AMPLITUDE-DEPENDENT INTERNAL-FRICTION OF HIGH-PURITY ALUMINUM

The dislocation amplitude-dependent friction (ADIF) of high-purity (99 .999%) polycrystalline aluminum is investigated in the temperature ran ge 7- 300 K at vibrational strain amplitudes of 10(-7)-10(-4) for samp les in the annealed and deformed (by quasistatic, shock, and ultrasoni c loading) states. The ADIF is a multistage effect in the indicated te mperature and vibration amplitude ranges. Analysis of the amplitude-te mperature spectra of the ADIF permits separation of components attribu table to: interaction between dislocations, the interaction of disloca tions with pinning points, and pure dislocation relaxation (the intera ction of dislocations with the Peierls relief). ADIF is observed to de pend nonmonotonically on the initial quasistatic strain determined by strain hardening and recovery processes. (C) 1998 American Institute o f Physics. [S1063-7834(98)01510-X].