Molecular dynamics simulation of the temperature effect on ideal mechanical properties of SiC/BN interface for SiC f /SiC composites
Résumé
Interfacial strength plays a significant role in the mechanical properties of SiCf/SiC composites. The understanding of the micro-mechanisms of interfacial strength on mechanical properties at different temperature is important in application of SiCf/SiC composite. In the present work, the interfacial properties of ideal tensile strength and fracture toughness of SiC/BN interface at different temperature were studied based on molecular dynamics. It is revealed that the interfacial strength of Case Si (Si-terminated SiC/BN interface) decreases with the increase of temperature, resulting in the decrease of tensile strength and fracture toughness, while the interfacial strength of Case C (C-terminated SiC/BN interface) basically remains unchanged; so the interfacial properties of Case C are less affected by temperature. This phenomenon is well explained in terms of stress distribution and interface bonding number. Our results provide a good theoretical explanation for the high-temperature service performance of ceramic matrix composites.