Internal friction of duralumin in a DC magnetic field

Abstract

As a result of an experimental study of the low-frequency (10 Hz) internal friction of D16 duralumin in dc magnetic fields with an induction 0 ≤ B ≤ 0.9 T at a temperature of 20°C, a maximum in the field dependence of the internal friction is detected in a field B ≈ 0.45 T. A numerical analysis of the experimental data is carried out using the Friedel amplitude dependence of the internal friction, which takes into account thermal displacements of dislocations in a crystal with impurities. The Friedel amplitude dependence is modified using the concept of the influence of a magnetic field on the probability of singlet-triplet electron transitions in the dislocation core-paramagnetic center (defect) system. Duralumin is used as an example to show that the modified Friedel dependence provides satisfactory agreement of the calculated data and the experimental data. It is concluded that the sensitivity of the low-frequency internal friction of D16 duralumin to a dc magnetic field measured at 20°C is due to the fact that mobile dislocations overcome impurity atoms of paramagnetic elements, in particular, titanium, because of thermal fluctuations. Internal friction can be used to determine the numerical values of the parameters characterizing the mechanical properties of metallic paramagnets in a dc magnetic field.