Nanotwinning-induced pseudoplastic deformation in boron carbide under low temperature

Structural and Stress Response of Nanotwinned B13CN under Large Strains

“…Boron-rich carbides (e.g., B 4 C and B 13 C 2 ) are exemplary cases among boron-rich compounds that exhibit unique properties of high hardness (30–50 GPa) and low density (∼2.5·gcm –3 ), with applications in body armor, cutting tools, and neutron radiation absorbents. − However, owing to low fracture toughness (3–4 MPa·m 1/2 ), B 4 C exhibits brittle failure under high pressure while forming amorphous shear bands. − To design and synthesize lightweight materials with excellent mechanical properties, various boron-rich compounds have been extensively explored, e.g., B 6 O, B 13 C 2 , and B 13 CN. − In boron-rich compounds, a B 12 icosahedron serves as the skeleton unit in which two-center two-electron (2c-2e) and three-center two-electron (3c-2e) bonding configurations coexist and exhibits unique bonding characteristics because of its electron-deficient nature. − The mechanical properties of boron-rich compounds are highly sensitive to their electron-filling states because of the electron-deficient icosahedrons and electron-compensating atomic chains. Thus, understanding their mechanical properties under various electron-filling states is crucial.…”