Anomalous Temperature-Dependent Interfacial Thermal Resistance Due to Melting

Ceramic composites are essential materials for high-performance applications in aerospace, defense, and other industries requiring high-temperature structural components and thermal barrier coatings. However, the understanding of heat transport processes at elevated temperatures, particularly at heterogeneous interfaces, remains in its early stages. In this study, we simulate the thermal transport properties of SiC/Si interfaces at various temperatures and uncover an unexpected anomaly. At high temperatures, the interfacial thermal resistance initially remains stable (consistent with the Acoustic Mismatch Model, AMM) but then decreases anomalously as temperature rises, which finally reaches a plateau as temperature further increases. This behavior results from the interplay between two factors: the gradual melting of Si, which increases the phonon density of states overlap between SiC and Si at the interface, and the gradual reduction in the structure factor of Si due to loss of long-range order. These effects together drive the reduction and subsequent plateau in thermal resistance at the heterogeneous interface in extreme high-temperature conditions. Our findings provide new insights into the complex role of interfacial melting in ultrahigh-temperature heat transfer and offer a theoretical foundation for the design and optimization of ceramic matrix composites for next-generation thermal management solutions in extreme environments.