MECHANISM OF FORMATION OF THE «HIGH-ENTROPY COATING/SUBSTRATE» INTERFACE DURING COLD METAL TRANSFER

10.25712/ASTU.1811-1416.2022.03.005

Abstract

The formation of the relief of the «high-entropy coating/substrate» interface surface during cold metal transfer is studied from the standpoint of ideas about the occurrence of Kelvin-Helmholtz and Rayleigh-Taylor hydrodynamic instabilities at the interface. It is shown that the presence of only the Kelvin-Helmholtz instability does not provide an adequate explanation for the formation of the wave-like relief of the «high-entropy coating/substrate» surface. Taking into account the acceleration of the layer (Rayleigh-Taylor instability) occupied by the coating of the Co-Cr-Fe-Mn-Ni alloy qualitatively changes the picture of mutual mixing of materials. When the transverse velocity of the layer is 50 m/s and the vertical component of acceleration is 107 m/s². The formation of vortices begins at t > 4 microseconds, and their decay into droplets occurs in the range from 8.4 microseconds to 22.5 microseconds. At t > 22.5 microseconds, the process of intensive mixing begins. With a non-zero horizontal component of the acceleration of the layers (a_y/a_x ~ 0.5), the fragmentation of vortices will occur in the range from 16.5 microseconds to 23 microseconds, and intensive mixing of the substance of the layers begins at t > 23 microseconds. It is shown that under these conditions, the calculated configuration of the upper room of the «coating/substrate» section coincides with the one observed in the experiment. The sizes of the formed particles range from 57 to 127 microns, which approximately corresponds to experimental data.