Micromechanical Deformation

这个项目的目的是研究几种可以用于研究微机械变形的技术。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。采用连续压痕测试实验作为一种新技术来测定沉积薄膜与衬底之间的粘附强度，以及测量薄膜本身的杨氏模量和泊索比值。对锌的晶界和三重结的压痕蠕变试验进行了分析。对玻璃和聚合物进行划痕测试，以了解粘/滑过程。原子力显微镜可以观察非晶金属的剪切带（带有磁性压头）以及聚合物中的微剪切带和裂纹。对非晶金属在车轮侧和空气侧的连续压痕试验进行了比较。理论分析包括有限元计算、分析方法、分子动力学和所有测试中关键步骤的建模。这些研究旨在回答与这些技术的使用和所选材料的微机械变形行为相关的问题。该结果将影响用于微机械测量、玻璃抛光和研磨以及薄膜和涂层与基材的附着力改善的技术。＊＊＊

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. ***