Material removal mechanism and penetration depth modeling of CF/PEEK composites under nano-scratching

Abstract

In order to investigate the material removal mechanism of carbon fiber-reinforced thermoplastics (CFRTP), nanoscratching experiments of carbon fiber-reinforced polyetheretherketone (CF/PEEK), as a typical kind of thermoplastic composite, were performed along various feed directions of the indenter and fiber orientations. Material removal mechanism was researched based on surface and subsurface morphological features. Experimental results indicated that chips were easily attached to the sample surface and difficult to remove, while chips containing much resin tended to accumulate and were tough to break. In addition, under the radial load, it was often observed that the interface remained still well, even though the breaking occurred inside the fibers during the scratching process. And under the axial load, there was crack deflection near the resin which inhibited the cracks expansion between the fibers. Furthermore, a penetration depth modeling to the normal load for CF/PEEK nanoscratching was developed, taking into account the impacts of elastic recovery, anisotropy, heterogeneity and stress distribution of material. Experimental validations showed that the prediction results evaluated by theoretical model was close to the actual results.