Crystalline-to-amorphous transition in silicon carbide under neutron irradiation

Low-temperature investigations of ion-induced amorphisation in silicon carbide nanowhiskers under helium irradiation

“…Several studies have reported a very small change in critical dose with increase in temperature for various single-crystal SiC polymorphs for temperatures below 277 K and above this temperature the critical dose increased rapidly [37], [57], [58]. This temperature is defined as the critical temperature for amorphization, Tc above which the material remains crystalline [32], [34]. This temperature is consistent with the ⁓290 K critical temperature reported here for the foil samples.…”

“…Previous computer simulations and experiments have revealed that ion-induced amorphisation occurs due to Si-C bond breaking followed by subsequent Si-Si/C-C homonuclear bond formation and also due to cascade overlap during displacement spikes within the SiC network [16], [34], [35]. These Si and C defects increase the Gibbs free energy which can be reduced by a transition to an amorphous state [34]. Amorphisation in turn causes substantial lattice swelling in the material that subsequently affects its mechanical properties [7], [14], [36], [37].…”

“…Ishimaru et al [38] using 200-300 keV electrons at room temperature observed a non-flux-dependant crystalline-to-amorphous transformation of 6H-SiC with a subsequent transformation to amorphous silicon attributed to preferential displacement of C atoms. Inui et al [39] reported electron-induced amorphisation at room temperature at 2 MeV at a critical dose of 1.1 dpa in 6H -SiC while Jamison et al [17] reported amorphisation of nanocrystalline 3C-SiC at a dose of 2.26 dpa after irradiation with 1.25 MeV electrons at 173 K. Snead et al [40] reported complete amorphisation of 6H and 3H-SiC after neutron irradiation to a dose of 2.5 dpa at room temperature while Jin et al [34] using molecular dynamics reported a neutron-induced crystalline to amorphous transition at a dose of 0.27 dpa in 3C-SiC. Heavy ion irradiation has also been shown to cause amorphisation in SiC with the critical dose decreasing with increasing ion mass which has been attributed to an increase in the residual disorder per ion impact [16], [36], [41]- [47].…”

Suppression of shear banding in amorphous ZrCuAl nanopillars by irradiation

“…A force field formulated and parameterized for normal conditions, however, usually produces a much weaker short-range repulsion or even unphysical attraction which can cause atomic fusion (as in the case of the ZrCuAl EAM potential used here). A general feasible solution is to switch or modify the short-range repulsion with more appropriate forms, such as the Ziegler, Biersack and Littmark (ZBL) potential, [31][32][33] an ab initio-based two-body repulsive potential, 34 the Coulomb potential, 35 or the Lennard-Jones (LJ) potential. 35,36 Although LJ potential is considered to be too hard for high-energy collisions, 37 it was chosen in this study due to the scarcity of experimental irradiation data for MG systems as well as the low irradiation energies that were considered in this work.…”

Radiation-Induced Effects on Material Properties of Ceramics: Mechanical and Dimensional Properties

“…Different attempts were made to model the amorphization and dynamic annealing processes on the basis of point defect properties. [174][175][176][177] Another approach was based on the formation of a chemical disorder inducing a kind of glass transition. 178 MD simulations have shown that a total volume swelling smaller than 4% occurs for point-defect accumulation, during the first step of damage for low disorder fractions (<10%).…”