Micromechanical investigation of heterogeneous microplasticity in ceramics deformed under high confining stresses

Modeling nonlinear electromechanical behavior of shocked silicon carbide

“…Superscript i corresponds to a particular slip system with resolved shear stress i . Merala et al 2 noted that secondary slip on prism planes may occur in shock-loaded hexagonal SiC, and this mechanism was considered in the simulations of Zhang et al 40 At temperatures below 1400 K, partial dislocations are favored over full dislocations, with leading partials more mobile than trailing partials in 4H-and 6H-SiC. 16,42,79 In ␣-SiC, Q may depend on electric current to account for lowering of the energy barrier to dislocation migration under bias voltage.…”

“…The Peierls model has been posited as a reasonable estimate for slip resistance in other ceramics. Zhang et al 40 proposed shear strengths of 4.3 GPa for full basal dislocations and 7.5 GPa for full prism dislocations upon comparison of continuum simulations with data for polycrystalline normal and shear stresses from shock physics experiments. For slip of partial basal dislocations, Maeda et al 80 suggested a shear strength of W SF / b Ϸ 0.014 GPa.…”

“…8,13,37 Large dislocation densities have been measured in ␣-SiC subjected to explosive shock loading. 39 Zhang et al [40][41][42] developed a crystal plasticity model for hexagonal SiC incorporating dislocation glide on basal planes, possible slip on prism planes, and failure at amorphous regions in the vicinity of grain boundaries. 39 Zhang et al [40][41][42] developed a crystal plasticity model for hexagonal SiC incorporating dislocation glide on basal planes, possible slip on prism planes, and failure at amorphous regions in the vicinity of grain boundaries.…”

“…39 Zhang et al [40][41][42] developed a crystal plasticity model for hexagonal SiC incorporating dislocation glide on basal planes, possible slip on prism planes, and failure at amorphous regions in the vicinity of grain boundaries. [40][41][42] Isolated slip of leading partial dislocations was not considered explicitly, nor were temperature effects such as adiabatic heating, thermal expansion, and thermally enhanced dislocation mobility. Nontextured polycrystals were addressed; hence, electromechanical interactions were omitted in numerical simulations.…”

Fracture of nanoceramics with porous structure at shock wave loadings

“…Of particular interest are investigations into the deformation and fracture processes developing in nanostructured ceramics under pulsed and shock loading [1][2][3][4]. These investigations provide information on the fundamental strength properties of the materials.…”