Change in Texture of Deformed Copper Exposed to Cold Air Plasma

The changes in the microstructure and texture of M1 copper samples after plastic deformation by rolling and exposure to low temperature non-equilibrium plasma of a high-frequency capacitive discharge excited at a frequency of f = 5.28 MHz in air at low pressure ( p ~ 1 Torr) have been studied in the paper. The metallographic analysis showed that changes in the microstructure of samples are insignificant. The grain size does not change; the visualization of the structure is improved, and the clarity of detection of grain boundaries is increased after metallographic etching. The results of X-ray structural analysis showed that the effect of plasma treatment leads to a change in the relative intensity of the interference lines of the X-ray diffraction pattern. After deformation, the prevailing orientation is á011ñ, which is typical for the texture of copper rolling. After exposure to plasma for 5 minutes, the intensity of lines (200), (220) and (311) increases. A slight increase in the relative intensity of the lines is observed after plasma treatment for 10 minutes. The parameter of the crystal lattice does not change after exposure to plasma. It was found that the change in the intensity of the X-ray lines is not associated with the action of microstresses or a change in the size of coherent scattering blocks. The ratio sinq (200) /sinq (111) = 1.15 indicates that stacking faults are not formed during plasma treatment. X-ray effects under plasma exposure are similar to those observed during tempering of deformed metals, when the main orientations of the deformation texture are either maintained at the level of the deformed metal or are enhanced. Under plasma exposure, the initial process of stress relaxation is realized, associated with the movement of atoms over distances smaller than interatomic distances, when the crystal lattice is improved. The main reason of the changes is third-order stresses, caused by the displacement of atoms from their equilibrium positions.