The behaviour of Boron Carbide under shock compression conditions: MD simulation results

HC Cekil and M Ozdemir, COMPUTATIONAL MATERIALS SCIENCE, 201, 110872 (2022).

DOI: 10.1016/j.commatsci.2021.110872

Boron Carbide (B4C) is investigated by molecular dynamics simulations to examine its mechanical behaviour on the dynamics loading. Atomistic shock compression simulations are carried out in 0001 and 10 (1) over bar0 impact directions for that purpose. Interaction between atoms is defined with reactive force field (reaxFF). Hugoniot curves are obtained and Hugoniot elastic limits (HEL) are determined for both directions. HEL point occurs at about 17 and 24 GPa in 0001 and 10 (1) over bar0 directions, respectively. Resistance of material to structural deformations is higher for 1010 direction compared to 0001. Three wave fronts develop in shock wave profile in the material. The shock velocity U-s- particle velocity Up relations in plastic region has bilinear nature. Amorphous state is observed above impact speeds 2.0 and 3.0 km/s, 0001 and 10 (1) over bar0 impact directions, respectively. Buckling of C-B-C chains and lattice rotation occur before amorphization, the degree of both of which depends on impact direction and these are considered the causes of deformation. The changes in the structural order of B4C is investigated using radial distribution function (RDF) analysis. Our numerical results compare favourably with available experimental results.

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