Micromechanics-based simulation of B4C-TiB2 composite fracture under tensile load

Micromechanics modeling was performed to study the effects of thermal residual stress, weak interphases, TiB2 volume fraction and particle size on the mechanical responses and fracture behaviors of B4C-TiB(2 )composites. Experimentally observed fracture behaviors including micro-cracking and crack deflection were successfully captured. The weak interphases at B4C-TiB2 boundaries and the thermal residual stress induced during cooling by the large CTE mismatch between B4C and TiB2 were identified as two major factors to promote micro-cracking that caused the enhanced progressive failure behavior. Micro-cracking was enhanced with higher TiB(2 )volume fraction due to higher fraction of weak interphase and material affected by thermal residual stress. Meanwhile, micro-cracking behaviors exhibited limited change with varying TiB2 particle sizes. This modeling study suc-cessfully captured the main fracture behaviors and their trends by varying micro-structures of B4C-TiB2 com-posites and can potentially aid microstructure design of tougher B4C-TiB2 composites in the future.

Automated summary

Micromechanics modeling was used to study the effects of weak interphases and thermal residual stress on the mechanical responses and fracture behaviors of B4C-TiB2 composites. Higher TiB2 volume fractions were found to enhance micro-cracking, while variations in TiB2 particle sizes had limited effect on micro-cracking behaviors.