Materials removal mechanism and multi modes feature for silicon carbide during scratching

Multi modes features during machining of brittle materials determine the process window. To reveal these fundamental features of SiC, a series of scratching experiments and atomistic simulations were designed. Real-time signals of scratching force and acoustic emission were analyzed in the time-domain and time-frequency domains to distinguish features. The birefringence of 4H-SiC in polarized light was non-destructively deployed to analyze the localized stress distribution and morphology after scratching. The experiments found four scratching modes - Hertz mode, quasi-ductility mode, high stress mode, and stylus failure mode. To reveal the atom-level behaviors inducing mode transition, atomistic simulations were conducted and post-analyzed from macro-level parameters, phase transition, dislocations, and so forth. The dynamic cycle mechanism - elastic deformation, plastic deformation, cracking - was revealed and the shear modulus, poisson's ratio, scratching speed, penetration depth, and deformation energy was recommended to optimize analytical model. Finally, we attempted to propose a unified qualitative multi layers model to explain different material removal mechanisms.

Automated summary

This study focused on the multi modes features during the machining of SiC, using scratching experiments and atomistic simulations. The scratching force and acoustic emission signals were analyzed to distinguish different scratching modes. The localized stress distribution and morphology were analyzed using non-destructive birefringence analysis. Four scratching modes were identified and atomistic simulations were conducted to understand the underlying atom-level behaviors. A qualitative multi layers model was proposed to explain different material removal mechanisms.