高强超延展性纳米MX相增强Cu基复合材料的研究

For the performance requirements of high yield strength and ductility in Cu-based materials applications, this project explores a preparation method of ultrafine grained Cu matrix composites based on the nano-MXx groups of MAX phases as nucleating agent and reinforment. The main research contents and the feature of this project consist in that,based on the nano-layered crystal structure of MAX ceramic materials, the characteristics of the A-site atoms can easily escape under the conditions of high temperature and the external force, use micro partice size MAX phase as precursor, to develop the nano-MXx group as nucleating agent and reinforced ultrafine grained Cu matrix composites, which possess high yield strength and ductility. Via researches on the key scientific problems such as the phase transition of MAX phase caused by reaction, the thermodynamic and kinetic mechanism, the interfacial reaction behavior, the formation mechanism and morphology of nano-MXx group, the nucleation and refinement mechanism of MXx group for copper, the rheological characteristics and deformation mechanisms of the composites, and optimize the conditions and means of preparing the composite material via the vertification of the refinement effect and the compression and tensile performance. This project reveals the refinement mechanism of nano-MXx group for Cu grain, the rheological characteristics and deformation mechanism, and the MAX phase transition, morphology and mechanisms caused by the reaction, provide a reference and science inspiration for the application of the nano-MXx reinforced ultrafine grained Cu composites, the improvement in the targeted performance and the preparation of other metal alloys and their composites to simultaneously elevate strength and ductility.

针对Cu基材料应用中高屈服强度高延展性的性能需求，本项目探索一种基于MAX相的纳米MXx基团为形核剂和增强体的超细晶Cu基复合材料。主要研究内容和特色是，利用MAX陶瓷材料特有的纳米层状晶体结构、高温及外力条件下A位原子容易逃逸的特性，通过对反应引起的MAX相的相变及热力学和动力学机制、界面反应行为、纳米MXx相的生成机制、组织形态等，MXx基团对Cu的形核细化机理及材料流变特性、变形机理等关键科学问题的研究，采用微米粒度的MAX相为先驱体制备具有高强度超延展性能的纳米MXx颗粒增强Cu基复合材料；并通过细化效果及压缩、拉伸性能的验证，优化相关制备方法及工艺。通过本项目的研究，揭示纳米MXx基团对Cu晶粒的形核细化机理和材料的流变特性及机理；揭示反应引起的MAX材料的相变机理；为纳米MXx/超细晶Cu复合材料的应用和针对性的性能改善及其他高强高延展性金属及复合材料的制备提供借鉴和科学启发。

针对Cu基材料应用中高屈服强度高延展性的性能需求，本项目采用微米粒度的MAX相（Ti3AlC2，Ti2AlC和Ti2SnC等）为先驱体制备具有高强度高延展性能的纳米MXx颗粒增强Cu基复合材料。通过对反应引起的MAX相变机理、界面反应行为、纳米MXx相的生成机制、组织形态等，MXx基团对Cu 的形核细化机理及材料流变特性、变形机理等关键科学问题的研究，获得了如下创新研究成果：.1）分别以较大的Ti3AlC2，Ti2AlC和Ti2SnC颗粒为先驱体，成功制备了具有高强度高延展性能的纳米TiC0.67和TiC0.5颗粒增强Cu基复合材料；.2）揭示了Ti3AlC2，Ti2AlC和Ti2SnC和Cu的不同反应行为，并阐述了反应引起的MAX材料的相变机理；.3）揭示了纳米TiC0.67和TiC0.5基团对Cu晶粒的形核细化机理和材料的流变特性及强化机理。.这些研究工作将对纳米MXx/超细晶Cu复合材料的应用和针对性的性能改善及其他高强高延展性金属及复合材料的制备提供借鉴和科学启发。部分研究进展和成果已发表论文15篇，申报发明专利8项，其中5项已获授权，培养博士生2名，硕士生7名，获2016年度北京市科技奖二等奖1项（公示已结束）。