金属纳米多层膜在冲击载荷下的力学行为和强化机制

Metallic multilayer in nanoscale has become one of the supporting basic for the development of high-tech technology in the future due to its excellent mechanical properties. Currently, a lot of research achievement has been obtained for the mechanical properties of FCC (face-centered-cubic) and BCC (body-centered cubic) nanoscale metallic multilayer in static and quasi-static, and its deformation mechanism and strengthening mechanisms have also been clear. However, relative reports about the nanoscale metallic multilayer with HCP (hexagonal-close-packed) structure is rare, and the dynamic mechanical properties of the nanoscale metallic multilayer and strengthening mechanism under the impact loading is still unknown. This topic focus on nanoscale metallic multilayer (HCP, FCC, BCC), preparing the metallic multilayer in nanoscale by using the magnetron sputtering method, obtaining the mechanical properties under tension loading at different temperatures and strain rate by means of systematic mechanical experiment. Nanoscale metallic multilayer model is established by the use of molecular dynamics (MD) simulation, and the strengthening mechanisms and microscopic deformation mechanism are explored from the evolution of dislocations, aiming at clarifying the dependence of mechanical behavior on the lattice structure and layered scales. The achievement of this topic is of great significance for the in-depth understanding the deformation mechanism and strengthening mechanism of nanoscale metallic multilayer, exposing the underlying relation between microstructure, dimension and the mechanical properties of metallic multilayers, and promoting its use in high-tech fields of aviation, aerospace, weapons, etc.

金属纳米多层膜由于其奇特的力学性能，已经成为未来高精尖技术发展的支撑基础之一。目前，针对FCC和BCC金属纳米多层膜在静态和准静态下的力学性能已有很多研究成果，其变形机理和强化机制也已明确。但是关于HCP金属纳米多层膜的研究鲜有报道，而且金属纳米多层膜的动态力学特性和在冲击载荷下的强化机制仍然未知。本课题以金属纳米多层膜（HCP、FCC和BCC）为研究对象，采用磁控溅射方法制备出纳观的金属多层膜结构，通过系统的力学实验获得其在不同温度、不同应变率下的拉伸力学性能，利用分子动力学模拟建立纳米尺度的金属多层膜模型，从位错演变的角度得到其强化机制和微观变形机理，明确其力学行为对晶格结构和层状尺度的依赖性。本课题的研究成果对于全面认识和深入理解金属纳米多层膜的变形机理和强化机制，揭示金属纳米多层膜材料微观结构和尺度与其力学性能之间的关系，推动其在航空、航天、兵器等高技术领域的应用具有重要的意义。

金属纳米多层膜材料凭借独特的结构和优异的力学性能，已经成为航空航天、电子通信、交通运输等高精尖领域发展的支撑基础之一。随着纳米多层膜的使役环境日益复杂，多层膜材料在各种工况下的力学行为受到了广泛关注。为满足不同领域对高性能纳米多层膜材料的需求，必须对纳米多层膜材料在不同条件下的力学行为进行系统研究。. 本项目的研究主要分四部分。一、HCP/FCC纳米多层膜的制备和微结构表征，对制备的Ti/Al及Ti/Ni多层膜材料进行表征，获得其微结构特征。二、金属纳米多层膜的纳米力学测试，揭示调制参数及应变率对多层膜材料力学性能的影响。三、Ti/Al层合板在不同温度、应变率下的宏观力学测试，获得层合板在不同工况下的力学行为及破坏机制。四、基于分子动力学的纳米多层膜材料的力学行为研究，利用模拟手段获得材料的微观变形机制和强化机制。. 通过研究，进一步探索了微结构对金属纳米多层膜的力学行为的影响，揭示微结构参数对其力学性能的影响，并提出相应的强化手段。本项目的研究成果，对推动纳米多层膜材料在高精尖领域的应用奠定了理论和实验基础。