Amplitude-dependent internal friction and dislocation inelastic strain in zinc and aluminium single crystals

Abstract

An experimental study of the amplitude-dependent internal friction, Young modulus defect and reversible inelastic strain in Al and Zn single crystals has been performed. The investigations were carried out in the low frequency (0.005-1 Hz) range. The amplitude—frequency spectra of the internal friction and Young modulus defect were analysed taking into account the quasi-static athermal component due to dislocation—dislocation interaction or internal stress field hysteresis and the thermally activated component due to dislocation interaction with point defects. The marked amplitude hysteresis and time dependence of the internal friction in Zn single crystals were attributed to point defect redistribution in the glide planes of mobile dislocations. The analysis of stress—inelastic strain hysteretic loops for Zn single crystals confirms the Kressel—Brown model of quasi-static internal stress field hysteresis.