The nanodimension crystallite formation in steel surface after pulsed plasma flow action

Abstract

The nanodimension crystallite formation in steel surface after pulsed plasma flow action Absract. This paper presents the analysis of structural-phase changes in samples of stainless steel AISI 321 (12Х18Н10Т) and AISI 201 (12Х15Г9НД), treated by pulsed plasma flows on coaxial plasma accelerator KPU-30. Studied the sequence of phase transitions in modified layers depending on a frequency of treatment. It is shown that after treatment with a small number of shots (n = 2) in the stainless steel samples occurs plasma etching and redistribution of crystallites. At tenfold (n = 10) processing the structure of the surface layer becomes more ordered, appear nanoscale columnar blocks evenly spaced on the surface and their tracks are located mainly at the grain boundaries. The results of SEM and AFM analysis showed the presence of surface melting; this suggests probable structural and phase changes during plasma processing. Changes in the structure of the investigated structural steels, associated with the formation of new phases and the microscopic strains in the crystal lattice, studied by XRD method.