Tensile failure mechanisms investigation of mesophase pitch-based carbon fibers based on continuous defective graphene nanoribbon model

• Published in: Materials & design Vol. 238; p. 112627
• Main Authors: Wang, Xinjie, Pan, Shidong, Wang, Xinzhu, Zhou, Zhengong, Zhao, Chengwei, Li, Dan, Ju, Anqi, Liang, Weizhong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2024; Elsevier
• Subjects: Atomistic model; Carbon fiber; Failure mechanism; Molecular dynamics; Failure mechanism; Molecular dynamics; Atomistic model; Carbon fiber
• ISSN: 0264-1275
• DOI: 10.1016/j.matdes.2023.112627

[Display omitted] •The developed atomistic model achieves Young’s modulus prediction error of under 5% for mesophase pitch-based carbon fibers.•The diverse strengths of interactions among adjacent graphene nanoribbons lead to the emergence of distinct failure modes.•Active graphene edges strengthen the defective region, thus modifying load redistribution and improving structure strength. Mesophase pitch (MPP)-based carbon fibers exhibit outstanding mechanical properties, notably an exceptionally high Young’s modulus. Despite extensive investigations into the microstructure of MPP-based carbon fibers, the influence of these factors on deformation mechanisms under tension remains unclear. This study employs the continuous defective graphene nanoribbons (dGNR) atomistic structure model for molecular dynamics simulations to explore the tensile failure mechanisms of MPP-based carbon fibers. In the simulation model, the structure of the defective region was generated through high-temperature annealing, and a transition region was introduced to prevent distortion and damage to the active graphene edges. The simulation reveals the evolutionary process of the microstructure of MPP-based carbon fibers under tension and achieves Young’s modulus predictions with greater accuracy than theoretical models. Additionally, the study shows that different strengths of interactions between adjacent graphene nanoribbons can lead to two distinct failure modes. Models with larger crystallite dimensions along the fiber axis and lower average defective concentrations exhibit geometric deformation coordination between adjacent nanoribbons, potentially elucidating the increasing strength trend in MPP-based carbon fibers with rising graphitization levels. Our simulations provide insights into the tensile failure mechanisms of MPP-based carbon fibers, offering valuable guidance for regulating their microstructure to enhance mechanical performance.