Models for the behavior of boron carbide in extreme dynamic environments

Abstract

We describe models for the behavior of hot-pressed boron carbide that is subjected to extreme dynamic environments such as ballistic impact. We first identify the deformation and failure mechanisms that are observed in boron carbide under such conditions, and then review physics-based models for each of these mechanisms and the integration of these models into a single physics-based continuum model for the material. Atomistic modeling relates the composition and stoichiometry to the amorphization threshold, while mesoscale

Thermodynamically-consistent derivation and computation of twinning and fracture in brittle materials by means of phase-field approaches in the finite element method

“…Nevertheless, boron carbide has strong anisotropic elasticity ( 𝐸 max 𝐸 min = 8.11, where 𝐸 max and 𝐸 min are the general maximum and minimum Young's modulus, respectively) (McClellan et al, 2001). This analysis is important because the plastic deformation in nanograined boron carbide is assumed to be dominated by intergranular fracture (Ramesh et al, 2021) and these new results can be employed towards guiding material design for B 4 C under extreme dynamic loading.…”

Thermodynamically-consistent derivation and computation of twinning and fracture in brittle materials by means of phase-field approaches in the finite element method

“…Nevertheless, boron carbide has strong anisotropic elasticity ( Emax E min = 8.11, where E max and E min are the general maximum and minimum Young's modulus, respectively) [204]. This analysis is important because the plastic deformation in nano-grained boron carbide is assumed to be dominated by intergranular fracture [205] and this new results can be employed toward guiding material design for B 4 C under extreme dynamic loading.…”

The effects of carbonaceous inclusions and their distributions on dynamic failure processes in boron carbide ceramics

“…During dynamic loading, the rate of increase of the load can outpace the finite growth velocity of the wing cracks initiated from the large carbonaceous inclusions. 22 Therefore, the carbonaceous inclusions next in size can also be activated and contribute to failure. Consequently, the entire distribution of carbonaceous inclusions is an important consideration when wing cracks dominate the failure.…”

“…Consequently, the entire distribution of carbonaceous inclusions is an important consideration when wing cracks dominate the failure. [22][23][24][25] Building on these previous works, and taking advantage of recent developments that allow for statistical and more detailed analysis of microstructure prior to and during deformation, this study presents a systematic investigation of the relationships between the distributions of carbonaceous inclusions and dynamic compressive failure through the wing crack mechanism. Our findings can help guide the design of new boron carbide ceramics with improved dynamic mechanical performance, and also help to understand the dynamic failure of other types of structural ceramics (e.g., SiC, Al 2 O 3 ) and brittle solids (e.g., geomaterials) that fail through formation of wing cracks from intrinsic flaws.…”

“…with 𝐺 and 𝜌 representing the shear modulus (assumed to be 197 GPa 22 ) and density (2.5 g/cm 322 ) of boron carbide. As seen in Figure 14, the normalized crack tip velocity was found to be higher for loading along the hot-pressing direction, which is consistent with the lower peak stress obtained in the through-plane orientation.…”