Epitaxy, Structure, Stress and Plastic Behavior in High Strength Metal Multilayers

本研究的目的是研究和优化外延金属多层膜的强化机制。先前的资助开发了通过溅射沉积生长和结构表征外延（001）取向FCC/BCC超晶格的能力。对这些材料的硬度进行了研究，发现与混合物相比，硬度提高了近300%。这一引人注目的现象是本期节目的主题。使用单取向外延薄膜，改变层的失配和相对厚度来推断塑性流动机制。结构表征涉及沉积和变形材料的高分辨率横截面透射电子显微镜，以便可以识别导致变形的原子尺度缺陷。该信息被合并到程序的建模组件中，该组件利用连续体和原子方法。这个程序的一个结果将是金属薄膜异常高的硬度。这些薄膜可以在半导体、信息存储和涂层技术中找到应用。此外，本课程应发展对层状材料和超薄膜塑性变形的基本理解。* * *

9408552 Clemens The purpose of this research is to investigate and optimize the strengthening mechanisms in epitaxial metal multilayers. A previous grant developed the capability for growing and structurally characterizing epitaxial (001) oriented FCC/BCC superlattices by sputter deposition. Hardnesses of these materials were investigated and enhancements nearly 300% found over the rule of mixtures. This remarkable phenomenon is the subject of this continued program. Using singly-oriented, epitaxial films, both the mismatch and relative thickness of layers are varied to deduce plastic flow mechanisms. Structural characterization involves high resolution cross-section transmission electron microscopy of as-deposited and deformed materials so that the atomic scale defects responsible for deformation can be identified. This information is incorporated into the modeling component of the program, which utilizes both continuum and atomistic approaches. %%% One result of this program will be metal films of unusually high hardness. These films could find applications in semiconductor, information storage, and coatings technologies. In addition, this program should develop fundamental understanding about plastic deformation in layered materials and ultra-thin films. ***