Relaxation processes for high-frequency mechanical loading of metals deformed at low temperatures
O.I. Volchok and I.M. Neklyudov
National Science Center “Kharkov Institute of Physics and Technology” 1 Akademicheskaya Str., Kharkov 61108, Ukraine
Received September 15, 2016, revised November 7, 2016
Generalization and analysis of experimental data on the effect of high-frequency (~ 20 kHz) mechanical loading (ultrasonic irradiation) on pre-deformed cryogenic (77K) face-centered close-packed lattice and space-centered cubic lattice metals are made in the work. It is shown that with ultrasonic irradiation, the predominant dissipation of the energy of mechanical oscillations occurs at the boundaries of twins, which determines the processes of redistribution of dislocations in the accommodation zones of twin strips and the matrix and ensures the relaxation of internal stresses in these places. At the same time, the effectiveness of the boundaries of twins as stress concentrators is leveled, which reduces the cold-brittleness of metals and enhances the contribution of the polygonization processes during subsequent annealing, delaying recrystallization. The obtained results substantiate the consideration of ultrasonic irradiation as an analog of local thermal activation and as a methodical technique of regulating the degree of conjugation of the phase-matrix interface.
PACS: 62.30. +d Mechanical and elastic waves; vibrations; PACS: 62.10.+s Mechanical properties of solid; PACS: 62.20. F– Deformation and plasticity.