The pre-stress scratching test investigation on silicon carbide ceramics

Based on the theory of pre-stress machining, In this paper the pre-stress scratching test was carried out on SiC ceramics, and the single-point diamond indenter moved with uniform speed under constant normal load. Combining with acoustic emission testing, the acoustic emission signal, the depth of scratch and the damage of surface / subsurface were analyzed under different pre-stress. The results showed that the existence of pre-stress can shorten the depth of median cracks and reduce the surface / sub-surface damage when adopting pre-stress machining method to study the machining of ceramic materials, moreover, with the increasing of pre-stress to a certain extent, the depth of median cracks were decreased and the propagation length of lateral cracks were shortened.