Mechanical behaviour of silicon carbide under static and dynamic compression

This paper compared the mechanical behaviour of 6H SiC under quasi-static and dynamic compression. Rectangle specimens with a dimension of 3×3×6 mm3 were used for quasi-static compression tests under three different loading rates (i.e., 10-5/s, 10-4/s and 10-3/s). Stress-strain response showed purely brittle behavior of the material which was further confirmed by SEM/TEM examinations of fractured fragments. For dynamic compression, split Hopkinson pressure bar (SHPB) tests were carried out for cubic specimens with a dimension of 6×6×4 mm3. Stress-strain curves confirmed the occurrence of plastic deformation under dynamic compression, and dislocations were identified from TEM studies of fractured pieces. Furthermore, JH2 model was used to simulate SHPB tests, with parameters calibrated against the experimental results. The model was subsequently used to predict strength and plasticity-related damage under various dynamic loading conditions. This study concluded that, under high loading rate, SiC can deform plastically as evidenced by the development of non-linear stressstrain response and also the evolution of dislocations. These findings can be explored to control the brittle behaviour of SiC and benefit end users in relevant industries.