三维连续石墨烯骨架填充铜基电子封装材料的强化传热机理研究

As the novel electronic packaging material, copper matrix composites filled with graphene were widely studied for the combination of high thermal conductivity (TC) of copper and low thermal expansion, low density, and high TC of graphene. While, the TC is restricted due to the interface boundary scattering effect on the electron transport (copper) and phonon transfer (graphene) generated by the random dispersion of graphene in copper matrix. To address the interface scattering problem, a new type of three dimensional graphene skeleton (3DGS) is proposed and will be prepared using nano-electrospinning/ chemical vapor deposition techniques in this project to build 3D continuous paths for phonon transfer in graphene to enhance the TC of composite material. The effects of 3DGS microstructure on TC of the Cu-3DGS composite material will be investigated through experiments and multi-scale numerical simulations to illuminate the effect of graphene topologies and parameters of graphene skeleton on the TC, to reveal the heat transfer mechanisms in the 3DGS structures. The effect of interface structure on the heat transfer behavior is studied from the micro-nano scale viewpoint. The achievements of this project can provide both theoretical and practical guidance for exploring the fabrication techniques of the copper matrix electronic packaging materials, revealing the micro-mechanisms of interfacial heat transfer, and enhancing the TC of copper matrix materials.

石墨烯填充铜基复合材料结合了铜高热导率和石墨烯低热膨胀系数、低密度和高热导率等优点，使其在新型电子封装材料领域受到广泛研究。然而铜基体中石墨烯弥散分布形成的相界面对传热电子/声子产生散射效应，制约复合材料热导率的提升。针对界面散射造成复合材料热导率降低的问题，本项目提出纳米纺丝/化学气相沉积方法，在铜基体中构建三维连续石墨烯骨架结构（3DGS），为石墨烯面内传热声子运动提供三维连续导通路径，强化复合材料的热导率。拟通过实验检测结合多尺度数值模拟，研究骨架微观结构对复合材料热导率的影响机制，阐明石墨烯拓扑结构、骨架特征参数对复合材料热导率的影响规律，揭示石墨烯骨架的传热机理；从微纳尺度揭示界面结构对Cu/C相界面传热行为的影响规律。研究结果对于强化铜基复合材料的热导率，探索新型铜基电子封装材料的制备工艺，揭示相界面的微观传热机制，具有重要的科学价值和工程应用价值。

本项目针对铜基复合材料作为电子封装材料面临的热导率、强度与热膨胀系数协同提升过程中面临的矛盾，通过在铜基体构建具有三维连续石墨烯填料结构，为导热声子提供传输通道，实现铜基复合材料“热-力”协同提升。项目通过多尺度数值模拟与实验验证相结合研究了石墨烯骨架结构特征对骨架本征性能及复合材料宏观性能影响规律。项目提出对铜-石墨烯相界面进行合金元素修饰，在改善铜-碳相界面润湿性的同时提高界面导热性能。项目研究结果揭示了不同种类合金元素对铜-石墨烯相界面导热影响机理，阐明了合金元素对铜-石墨烯相界面导热强化机制。项目通过实验与数值模拟相结合对铜-石墨烯相界面载荷传递行为进行研究，揭示了石墨烯对相界面区域铜基体通过强烈的弹性回复作用强化铜基体形变抗力，该结果为准确设计与调控石墨烯强化金属基复合材料的力学性能提供理论依据和设计准则。针对铜石墨烯复合材料热膨胀系数调控，本项目提出对相界面几何结构进行调控，构建铜石墨烯相界面曲率半径-界面残余热应力-界面残余热应变-界面瞬态热膨胀系数之间的定量关系，获得了随温度升高热膨胀系数降低的复合材料相界面结构设计方法。上述成果为设计高导热系数、高力学强度和低热膨胀系数兼顾的铜石墨烯复合电子封装材料提供了理论研究基础和设计准则，具有非常重要的实用价值。