|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Computational Materials Discovery and Optimization
||Improving the Ductility of Boron Carbide from Computational Design
||Qi An, William A Goddard III
|On-Site Speaker (Planned)
Ceramics such as boron carbide (B4C) are strong but too brittle for extended Engineering applications. The large-scale reactive-molecular-dynamics simulations were performed on shear deformations of B4C and found that brittle failure in B4C arises from formation of higher density amorphous bands due to fracture of the icosahedra. This leads to negative pressure and cavitation resulting in crack opening. This suggested two design strategies to improve the ductility of B4C: (1) Replacing the three-atom C−B−C chains with two-atom chains to eliminate the highly reactive central B atom; (2) Making sure that the strength of the two-atom chain is less than that of the icosahedron. To prove these principles, the quantum mechanism (QM) simulations were performed and show that under shear deformation boron subphosphide (B12P2) deforms through breaking and then reforming the P-P chain bonds without fracturing the (B12) icosahedra. Thus, stress accumulated as shear increases is released by such deformation mechanism.
||Planned: Supplemental Proceedings volume