Plastic deformation and modification of surface characteristics in nano- and micro-levels and enhancement of electric field of FCC materials using cavitation phenomenon

Abstract

The aim of this paper is to demonstrate and establish a possible application of the cavitation phenomenon as an efficient method to modify surface properties. Three FCC (Face Centered Cubic) materials were subjected to high speed submerged cavitating jets under certain working conditions, for time periods between 15 and 1800 s. The force generated by cavitation is employed to modify the surface roughness in nano- and micro-scales. The target surface was investigated with digital optical microscopy, atomic force and electrostatic force microscopy (AFM and EFM) and also with a white light interferometer. These different observation techniques indicate that at short exposure times, the observed characteristic features in the microstructure – hills, holes and wavy configuration – can be related to the start of the plastic deformation of the specimen surface. Longer exposure times inevitably result in a greater number of jet specimen interactions leading to specimen erosion and fracture. The results demonstrate the possibility to use cavitation bubbles as a micro-nanofabrication method for the surface preparation/modification or shoot-less surface peening. EFM results present a possibility of using cavitation as tool to enhance the electrostatic properties of a metal surface by modifying its roughness. The degree of enhancement depends on the material properties.