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Micro-grained diamond-SiC composites have been prepared by sintering a mixture of micro-grained diamond and Si powder using high-temperature and high-pressure method at 1100–1500 ° C , and 5.5 GPa. Plate impact experiments in reverse—and forward—impact geometry were used to investigate the shock response of the micro-grained diamond-SiC composites within a shock pressure range from 22 to 195 GPa. The obtained plot of shock velocity (D) vs particle velocity (u) indicated that the double elastic wave responses are observed in the pressure range of 22–170 GPa, which is consistent with the previously reported diamond-SiC composites containing a small amount of tungsten carbide (WC) under shock compression up to ∼ 110 GPa [Li et al., J. Appl. Phys. 128, 245901 (2020)]. The results of shock experiments demonstrate that the Hugoniot elastic limit of micro grained diamond in SiC matrix is as high as 170 GPa, which is nearly twice as high as that of single crystal diamond. [ABSTRACT FROM AUTHOR]

We have synthesized the well-performance bulk diamond–SiC composite by the high-temperature and high-pressure method and employed the light gas gun launched flyer plates to investigate shock compression response of the diamond–SiC composite. The plots of shock velocity vs particle velocity demonstrate the presence of double elastic waves in the diamond–SiC composite under shock compression. The first elastic wave travels at 13.1 ∼ 13.6 km / s and leads to yielding at ∼ 12.75 GPa. The second elastic wave propagates at 12.8 ∼ 13.0 km / s and does not display the yielding up to ∼ 110 GPa. Such a Hugoniot elastic limit is apparently higher than that of the single crystal diamond. The strengthening mechanism underlying the diamond–SiC composite has been discussed. By simulations of the lattice-spring model, the results revealed that under shock compression, the silicon carbide matrix yields first in the composite, resulting in damage to the substructure surrounding the diamond particles. This damage releases the intense shear stress and protects the diamond from severe crushing. Due to diamonds being hydrostatically confined by the silicon carbide matrix, both dislocation migration and slip band sliding are suppressed significantly, which enhances the strength of diamonds. [ABSTRACT FROM AUTHOR]