Behavior and damage of the near-surface layer of parts pre-machined by the EDM process Experimental characterization and numerical simulation

This paper presents an experimental investigation and numerical modeling of the mechanical behavior and damage of the near-surface layer of mechanical parts, pre-machined by the EDM process. The intended purpose is therefore to understand and then predict the impact of this process on the service life of machined parts. In situ mini-tensile tests under XRD were performed to characterize the mechanical behavior of the near-surface layer preloaded by the residual stress and strain-hardening gradients previously induced by the EDM process. These tests were also used to identify the parameters associated with the numerical model. The results of this study revealed that the interface between the base material and the near-surface layer is the seat of a significant incompatibility of plastic deformations, which accelerates the rate of damage in this zone and supports the development of microcracks. This cracking tendency is enhanced by the omnipresence of residual stress and strain-hardening gradients.