Study on Indentation Experiments and Mechanical Behavior of RB-SiC

In this work, we studied on the mechanical behavior of RB-SiC by the indentation experiments. The Vickers hardness tester and the laser scanning confocal microscope are used to process and observe the RB-SiC sample pieces. The indentations result shows that the hardness at the Si phase is lower than the SiC phase, thus it is easier to remove the Si than SiC. The morphology of indentations are complicated, there were no accumulation phenomenon at indentation edge. When the loading was 0.1kgf, 0.2kgf and 0.3kgf, only the radical cracking can be observed and the cracking was not obvious at Si and SiC mixed phase. Avalanche crushed phenomenon occurred when the load increased to 0.4kgf. According to the Evans' fracture toughness formula, the fracture toughness of SiC phase is about 2.5MPa.m(1/2), and the fracture toughness of Si-SiC mixed phase is bigger than 3.0 MPa.m(1/2). The critical cutting depth (d(c)) of RB-SiC was calculated by empirical formula presented by T. G. Bifano, and the value is 22.54nm.