纳米叠层结构镁/钛块材可控制备及其高强高稳定机理研究

作为目前最轻的金属结构材料，镁基材料在航空航天领域极具应用潜力，但强度偏低和热稳定性差，极大地限制了其应用。针对上述问题，本项目基于金属镁(Mg)与钛(Ti)不互溶原理设计热力学稳定的Mg/Ti相界面，拟通过正交累积叠轧焊(CARB)方法在镁基材料内部构筑Mg/Ti纳米叠层结构，以期实现强度与热稳定性同步提高。通过研究CARB过程中层厚由宏观尺寸向微米尺寸，再到纳米尺度转变过程中，Mg/Ti两相的织构演变和界面结构演化规律，实现Mg/Ti叠层材料可控制备。采用力学性能测试、高温退火和微结构分析等方法，研究层厚尺寸、变形织构、相界面结构等微结构参量对材料力学性能、热稳定性的影响规律，澄清Mg/Ti纳米叠层构型的尺度和界面效应，阐明“CARB工艺—纳米叠层构型—宏观性能”间的关联响应机制。项目的研究成果将为镁基材料的性能优化及其应用提供科学依据，也为其他高强、高稳定材料的研发提供新思路。

Magnesium-based materials, as the lightest structural metallic materials, offer significant potential for aeronautic and aerospace applications. However, low strength and poor thermal stability have limited their applications. In order to simultaneously achieve high-strength and high thermal stability in bulk Mg-based materials, the current project is going to design and synthesize bulk nanolayered Mg/Ti composites based on the immiscibility principle of Mg with Ti by integrating heterophase interface architectures and cross accumulative rolling bonding (CARB) technique. Controllable preparation of bulk Mg/Ti nanolayered composites will be realized by systemic investigation of the evolutions of texture and interfacial structure with layer thickness dimensions from macro-meter to micro-meter and to the nanometer. By means of the mechanical properties testing, microstructure observation, and high temperature annealing, the influence of layer thickness, rolling texture and interface structure on the mechanical properties and thermal stability of the Mg/Ti nanolayered composites will be investigated systematically so as to understand the interface and size effects in Mg/Ti nanolayered composites, and explore the relationships of CARB fabrication processing–nanolayered structure–performance of the bulk nanolayered Mg/Ti composites. The achievements of this project will afford scientific basis for synthesis and applications of high performance Mg-based materials in the future. Moreover, the present project will provide new method for research and development of other materials with high strength and high stability.