Multi-tip indenter tool scratch behavior of glass-ceramics

Abstract

To reduce the surface flaws and subsurface damages of glass-ceramics as clinical substitute and repair materials, it is necessary to clarify the material removal behaviors and crack propagation modes in the grinding process. In this paper, a multi-tip indenter tool was fabricated and assembled on a Nanomechanical testing system. The experiments of ramp load scratching with the single-tip/multi-tip indenter tools were conducted on glass-ceramics to compare the material removal behavior under different scratch methods. The surface morphology, subsurface cracks propagation, and the brittle-ductile transition region were observed and investigated. Based on the scratch experiments, the finite element simulation model was established to analyze the stress characteristics in the glass-ceramics. The result shows that in multi-tip scratches, as the depth of scratch increases, the growth of surface cracks mainly takes three forms. Compared with non-instant multi-scratch, instant multi-scratch makes the propagation path of lateral cracks closer to specimen surface, suppresses the propagation severity of lateral and median cracks, and increases the depth of brittle-ductile transition region. This paper's results provide a fundamental understanding of multiple abrasive grains instant interaction on the material removal mechanism, and help to improve the clinical performance of glass-ceramics as biomedical materials.

Keywords: Glass-ceramics; Grinding; Material removal mechanism; Scratch tests.