强各向异性Be薄膜的晶粒细化和应力弛豫机制研究

项目名称： 强各向异性Be薄膜的晶粒细化和应力弛豫机制研究

项目编号： No.11204280

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 罗炳池

作者单位： 中国工程物理研究院激光聚变研究中心

项目金额： 26万元

中文摘要： 在聚变能（IFE）实验研究中，需要用到各向同性且低应力的Be薄膜材料。Be薄膜在生长过程中原子以hcp结构排列，晶粒c轴取向，以粗大柱状晶为主，薄膜呈现强各向异性。另外，在薄膜制备过程中应力产生在所难免，它会引起薄膜变形和开裂，这些降低了Be薄膜力学性能和烧蚀特性，破坏了良好的冲击波阵面形成，限制其在IFE中的应用。本项目基于经典形核理论，拟通过施加强磁场和超声场来降低临界形核尺寸和阻止晶粒外延生长，实现薄膜晶粒细化。结合薄膜原位退火和分级热处理技术，借助热扩散来减少薄膜在非平衡生长过程中形成的缺陷和位错，进而降低薄膜残余应力。深入研究Be粒子在基体上凝结、成核、长大的动力学过程，建立薄膜晶粒尺寸随外场强度的函数关系，采用XRD-sin2ψ法表征薄膜残余应力，并揭示薄膜应力弛豫机制.

中文关键词： 铍薄膜；微观结构；晶粒细化；残余应力；超声场

英文摘要： The beryllium film with the isotropy characteristics and low residual stress is required in the physics experiment for inertial fusion energy (IFE). During the Be film growth, the Be atoms array in the form of hcp structure, and the crystal grains grow along c-axis orientation. The Be film is mainly characterized by a large size columnar grain, and displays a strong anisotropy characteristics. In addition, the residual stress in Be films produces unavoidablly. It will lead to distortion and cracking of film. These disadvantages reduce the mechanical property and ablation characteristics for Be films, as well as destroy the formation of favourable shock-wave face. The Be film is restricted to use in IFE. The objective of this project is to achieve grain size refinement for the strong anisotropy Be film. On the basis of the classical nucleation theory, we try to control critical nuclear size and prevent from the grain extension growth via coupling the new methods of a strong magnetic field and an ultra-sound field, and plan also to reduce the formation of film defects and dislocation during the non-equilibrium growth by in-situ anneal processing or heating-up processing. Further, we investigate the dynamics process of Be particles, such as coagulation, nucleation and growth. Some relationships between grain size a

英文关键词： beryllium thin film；microstructure；grain size refinement；residual stress；ultrasonic field