Relaxation mode of macroscopic plastic deformation in metals

The relaxation of elastic energy during macroscopic plastic deformation in a strict formulation is determined by the solutions of the system of nonlinear equations of mechanics of a deformable solid. Using the methods of the theory of nonlinear systems, a nonlinear parabolic equation is obtained for the amplitude of an unstable mode, which describes plastic deformation at large spatial and temporal scales.

The Nanometer Scaled Defects Induces with the Dislocation Motion in II-VI Insulated Semiconductors

Dislocation-related defects induced by dislocation motion in p-CdTe were studied. Generation of “fresh” dislocations from the indented point of the CdTe (100), (110), and (111) surfaces at room temperatures was visualized by the chemical etching and low temperature photoluminescence in a mapping regime. The crystallographic orientation of the dislocation rosettes of macroscopic plastic deformation lines was analyzed on the (100), (110), and (111) surfaces.

Discountinuity of Plastic Flow Controlled by Magnetic Field in NaCl:Eu Crystals

An influence of a constant magnetic field (MF) with induction up to 15 T upon macroscopic plastic deformation of diamagnetic NaCl single crystals containing paramagnetic Eu impurity was observed. Effects of MF on instability of plastic flow (on the Portevin-Le Chatelier effect) in quenched NaCl:Eu crystals were found. The MF results in a decrease of the yield stress, a decrease of the probability of the instability appearance, and a decrease of the averaged magnitude of the deformation jumps, as well as in a chaotization of the distribution of the deformation jump magnitudes. The latter can be explained by partial plastic relaxation of internal stresses under MF that was confirmed by dislocations displacement induced by internal stresses in MF. The averaged amount of shear bands observed on the surface of the investigated crystals deformed under MF is half of that in reference specimens.