MAX弱键解离内生TiCx+Al2O3/Cu材料可控制备及界面-性能耦合作用机理研究

It is crucial to obtain uniform distribution of reinforcements and preparation methods effectively controlling interfacial reactions for the development of advanced copper matrix composites. The excellent wettability between non-stoichiometric TiCx and copper provides a possibility to solve above problems. This project make full use of the weak combination between atoms of the typical MAX phase ceramic materials of Ti2AlC, and then in-situ produce Al2O3 particles via strong reactivity between Al and Cu2O, it can overcome the problem of lower conductivity caused by Al atom diffusion, and effectively improve the abrasive resistance. At the same time, Ti2AlC decompose into minuteness TiCx of dispersed distribution, and to coordinate the matching relation between electrical conductivity, strength, plasticity and friction performance. Firstly, the thermodynamics and kinetics of a serial of synthetical reactions in Ti2AlC-Cu2O system is clarified. Then, the formation mechanism of TiCx and Al2O3 and the main factors effect the reinforcements characteristics are revealed. Meanwhile, the strengthening and conductive mechanism of composite materials are analyzed, the coordination deformation behavior and the wear behavior are confirmed, and also the strengthening model, and coordination deformation model are constructed. Finally, the TiCx-Al2O3/Cu composites with high strength and ductility, high conductivity and good wear resistance are controllable fabricated through theoretical models forecasting, process parameter optimization and organization performance controlling. This project has important scientific value for the theory research of interface, synergetic strengthening and tribological mechanism.

增强体的弥散分布和界面行为的有效控制是发展先进铜基复合材料的关键。非计量比TiCx与Cu之间良好的浸润性为解决上述问题提供了可能。本项目利用典型MAX相Ti2AlC弱键解离特性促使Al原子脱嵌扩散，并与Cu2O反应生成Al2O3，克服Al原子扩散引起导电率下降的同时改善耐磨性能，且造成Ti2AlC分解获得微细纯净TiCx以协调导电性、强度、塑性和耐磨性之间的匹配关系；阐明Ti2AlC-Cu2O体系原位自生TiCx-Al2O3/Cu的反应热、动力学及界面反应机理，揭示TiCx和Al2O3的形成机制，剖析复合材料的强化和导电机制，明确变形行为和摩擦磨损行为，构建协调变形及协同强化模型，并通过模型预测、工艺优化和组织性能调控，实现高强韧、良导电、耐磨损的TiCx-Al2O3/Cu复合材料的可控制备。项目的顺利开展对于促进金属基复合材料界面科学、强韧化和摩擦学关键共性问题研究，具有重要的科学意义。

增强体的弥散分布和界面行为的有效控制是发展先进铜基复合材料的关键。TiC-Cu复合材料因其具有高强高导、耐高温、耐磨及耐电弧侵蚀等诸多性能优点而广泛应用于航空航天、电子信息、轨道交通、国防军工等诸多领域。本项目以Ti2AlC-Cu2O-Cu为研究对象，利用Ti2AlC前驱体易于发生结构性改变的特性，采用粉末冶金技术原位自生TiC0.5-Al2O3/Cu复合材料，阐明了体系原位制备TiC0.5-Al2O3/Cu复合材料的反应热力学及界面反应机理，掌握了Al原子的扩散行为、Ti2AlC的分解过程、复相增强相的形成过程，重点研究了制备工艺条件参数对复合材料组织结构和性能的影响规律，建立了制备条件-微观组织-宏观性能之间的内在关系，明确了复合材料的变形机制及摩擦磨损机理，主要研究内容和重要结果有：（1）热力学分析和第一性原理计算结果表明了体系的目标反应产物为TiCx和Al2O3；（2）界面行为研究表明随着烧结温度的升高，界面反应程度加剧，反应层厚度增大，复相增强体颗粒含量增加，且进一步证实了体系反应产物为TiC0.5和Al2O3，其中Al2O3为混合晶型；（3）烧结温度、成分设计以及Ti2AlC颗粒尺寸等对复合材料的组织性能影响显著，且当烧结温度为980℃，Ti2AlC平均粒度为0.81μm，Ti2AlC添加量为3wt.%时，复合材料综合性能最优；（4）冷加工变形能在保持复合材料较优塑性的前提下进一步提高复合材料的力学性能和导电性能，摩擦磨损性能分析结果表明复合材料的磨损机制为典型的粘着磨损和磨粒磨损。项目的研究成果对于促进金属基复合材料界面科学、强韧化和摩擦学关键共性问题研究，具有重要的科学意义。