Plasticization of face-centered metals under electron irradiation

Abstract

The effect exerted by an electron beam with an energy of 0.5 MeV on the deformation of polycrystalline aluminum (99.5%) and copper (99.5%) under uniaxial tension at a rate of 2 × 10−4 s−1 in the temperature range from 40 to 100°C has been investigated. It has been established that the plasticity of the metal increases under irradiation with an electron beam: the level of the flow stress and the strain hardening coefficient in the irradiated state decrease, whereas the total resource of plasticity of the material increases. A mechanism of an increase in the plasticity of metals has been proposed. This mechanism is based on the radiation-induced generation of nonlinear strongly localized excitations of the crystal lattice, namely, discrete breathers, whose lifetime is significantly longer than the relaxation time of phonons. The interaction of discrete breathers with dislocations can stimulate the detachment of dislocations from stoppers and, consequently, an increase in the plasticity of the material.