Micromechanical Deformation

9623808 Li本项目的目的是研究可用于研究微机械变形的几种技术。这一组包括原子力显微镜、连续压痕测试、压痕蠕变机和划痕测试仪。连续压痕实验是一种测定薄膜与衬底之间结合强度的新技术，也是一种测量薄膜本身的杨氏模数和泊松比的新技术。分析了锌中晶界和三结点的压痕蠕变试验。对玻璃和聚合物进行划痕测试，以了解粘结/滑移过程。原子力显微镜观察非晶态金属中的剪切带(带有磁压头)以及聚合物中的微观剪切带和银纹。比较了非晶态金属在轮侧和空气侧的连续压痕试验。理论分析涉及到所有测试中的有限元计算、分析方法、分子动力学和关键步骤的建模。这些研究的目的是回答与使用这些技术和所选材料的微观机械变形行为有关的问题。%这一结果将影响用于微机械测量、玻璃抛光和研磨的技术，以及提高薄膜和涂层与基材的附着力。***

9623808 Li The purpose of this project is to examine several techniques that can be employed in studying micromechanical deformation. Included within this group are the atomic force microscope, continuous indentation testing, the impression creep machine, and the scratch tester. Continuous indentation testing experiments are employed as a new technique to determine the adhesion strength between a deposited thin film and the substrate, as well as measuring Young's modulus and PoissonOs ratio of the film itself. Impression creep machine tests of grain boundaries and triple junctions in zinc are analyzed. Scratch testing of glass and polymers is performed to understand the stick/slip process. The atomic force microscope looks at shear bands in amorphous metals (with a magnetic indenter) as well as micro shear bands and crazes in polymers. Continuous indentation testing of amorphous metals on the wheel side and the air side are compared. Theoretical analysis involves finite element computation, analytical methods, molecular dynamics and modeling of critical steps in all of the tests. The studies are aimed at answering questions associated with the employment of these techniques and the micromechanical deformation behavior of the selected materials. %%% The results should impact techniques used for micromechanical measurements, polishing and grinding of glasses, and improved adhesion of thin films and coatings to substrates. ***