Nano- and Micro-Scale Surface Modification of FCC Metal Using High Submerged Cavitating Water Jet

Abstract

The aim of this paper is to establish a possible application of the cavitation phenomenon as an efficient method to modify surface properties at the nano and micro levels. Commercial-purity copper was subjected to high submerged cavitating jets under different initial conditions, for time periods between 15 and 1,800 s. The force generated by jet cavitation is employed to modify the surface roughness in the order of nano and micro scales. The target surface was analyzed with optical as well as scanning probe electron microscopy. The results showed the possibility to use cavitation bubbles to establish a nanofabrication method for the surface preparation, shoot-less surface peening (nano/micro level). Also, the cavitation is assumed to be one of the miniaturized testing methods that have to be developed to reliably measure mechanical properties in small dimensions and to identify the behavior caused by the size dependence. With optical, SEM, and atomic force microscopy observation techniques in this study, the deformation mechanism and the formation of planar or wavy slip were also studied. The results indicate that even at short exposure times, observed roughness having a characteristic "serpentine" 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 jetspecimen interactions leading to specimen fracture.