复合微结构特征对BN/Cu界面导热行为的影响规律及机制

Metal-matrix composites with high thermal conductivity have great demand in aerospace and electronics industrial applications. Since microstructure characteristics (such as dislocation density, crystal orientation, elastic strain, etc) have complex effects on the thermal conductivity of interface, exploring their coupling effect can assist further improvement of the materials properties and fabrication process. In this project, we propose to design and fabricate a series of c-BN/Cu and h-BN/Cu bilayers and multilayers by magnetron sputtering, and investigate relationship between interface structure and interfacial thermal conductivity. The BN/Cu interface and adjacent regions will be used to mimic the interface region in composite materials. The different structures of c-BN and h-BN can be controlled by substrate orientation, deposition rates and substrate bias. The formation mechanisms of misfit dislocations in these films as a function of thickness will be examined. By studying the thermal conductivity of these films, the role of the microstructure characteristics including the crystal orientation, elastic deformation and dislocation density on the thermal conductivity of the interface will be further revealed. Based on the experimental results and the existing interfacial thermal conductivity models, a modified model considering the coupling relationship between the interface microstructural parameters and the interfacial thermal conductivity will be established. This project will be beneficial to the synthesis of high thermal conductivity copper-matrix composites.

高导热金属基复合材料在包括空天和电子在内的诸多领域有重大需求，复合微结构因素（如位错密度、晶体取向等）对界面导热行为作用复杂，研究其影响机制可促进这类材料的制备优化和性能提高。本项目拟采用将多种界面微结构因子加以“孤立”并单独改变的研究方法，通过磁控溅射技术制备一系列能够模拟复合材料界面（含邻近区域）的c-BN/Cu和h-BN/Cu双层和多层薄膜，并基于对各薄膜生长特征和界面结构的研究，揭示晶格失配度和层厚对金属层中位错密度的影响规律。通过对c-BN/Cu和h-BN/Cu复合薄膜与导热行为关系的研究，进一步揭示界面晶体取向、弹性形变、以及金属层中位错密度对界面热导的影响规律。结合以上实验研究结果和现有的界面热导模型，建立复合材料界面（含邻近区域）各微结构特征参数与界面热导耦合关系的模型，为高导热Cu基复合材料的界面优化设计提供实验和理论支撑。

高导热金属基复合材料在航空航天、微电子等领域具有重要应用前景，然而界面微结构特征（取向、厚度和缺陷等）对界面热阻影响机制复杂，使其导热性能的进一步提升受到显著限制。为揭示单一界面特征参数对界面导热行为的影响规律和机制，本项目以石墨烯/铜、金刚石/铜和氮化硼/铜界面为研究对象，围绕界面特征与界面声电散射及耦合行为的关键科学问题，开展了复合界面微结构调控和时域热反射界面热导测试等方面的研究。通过阐明界面微结构对界面导热性能的影响规律，揭示了界面特征对界面热载能粒子的作用机制，并基于界面声子反转弛豫时间和声子穿透系数，定量建立了界面特征-界面热导的内在关联性。当前研究结果可为通过调控和优化界面取向、厚度和缺陷等特征参数以实现高导热金属基复合材料的制备提供实验支撑和理论依据。