Indentation Mechanics of Monocrystalline Substrates

单晶衬底的压痕力学

• 批准号: 0084948
• 负责人: Pedro Peralta
• 金额: $ 17.61万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-10-01 至 2004-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0084948&HistoricalAwards=false
• 关键词: Indentation; Mechanics; Monocrystalline; Substrates

0084948PeraltaInstrumented sharp indentation provides valuable information on the mechanical properties of materials and is the test of choice when small volumes are involved. This is usually the case in single crystal studies, since they are often produced in small quantities and can be too delicate for conventional testing. Single crystal behavior is intrinsically anisotropic and so is the response of textured polycrystals and thin films, which are also often characterized using indentation. However, most of the models used to analyze hardness are isotropic and, therefore, cannot capture all the aspects of the anisotropic behavior of monocrystalline and/or strongly textured materials. Furthermore, models to account for crystallographic slip around indents on monocrystals do not seem to be available. It is then necessary to perform experimental and theoretical work to relate load-penetration data, slip and hardening behavior around indents on single crystals to their mechanical properties.A dual experimental/theoretical approach can be used to understand the effect of anisotropy on the indentation mechanics of materials. Monocrystals will be grown from selected materials and instrumented indentation tests performed on high symmetry planes. Profilometry, atomic force microscopy and reference grids will be used to determine surface displacements. The slip behavior around indents will be characterized using slip trace analysis and transmission electron microscopy. Meanwhile, small-scale yielding models for sharp indenters will be developed for anisotropic elasticity as well as models to account for plasticity due to crystallographic slip. These models will be used to obtain load-penetration curves and the evolution of the contact area between the sample and the indenter. Finally, correlations between the experimental data and basic material properties in single crystals, such as the elastic moduli and critical resolved shear stresses, will be established through the models. This project will also actively involve undergraduate and graduate students in experimental and theoretical research. ***

0084948 Peralta仪器化尖锐压痕提供了有关材料机械性能的宝贵信息，并且是涉及小体积时的首选测试。这通常是单晶研究的情况，因为它们通常是小批量生产的，并且对于常规测试来说太精细了。单晶行为本质上是各向异性的，织构多晶体和薄膜的响应也是如此，它们也经常使用压痕来表征。然而，大多数用于分析硬度的模型是各向同性的，因此，不能捕捉单晶和/或强织构材料的各向异性行为的所有方面。此外，模型来解释单晶体上的压痕周围的晶体滑移似乎是不可用的。因此，有必要进行实验和理论研究，将载荷-穿透数据、单晶压痕周围的滑移和硬化行为与其力学性能联系起来。实验/理论双重方法可以用来理解各向异性对材料压痕力学的影响。单晶将从选定的材料和仪器压痕测试高对称平面上进行生长。将使用轮廓测定法、原子力显微镜和参考网格来确定表面位移。压痕附近的滑移行为将使用滑移痕迹分析和透射电子显微镜来表征。同时，小规模的屈服模型的尖锐压头将开发各向异性弹性以及模型，以考虑塑性由于晶体滑移。这些模型将用于获得载荷-穿透曲线以及样品与压头之间的接触面积的演变。最后，实验数据和单晶中的基本材料性质之间的相关性，例如弹性模量和临界分解剪切应力，将通过模型建立。该项目还将积极吸引本科生和研究生参与实验和理论研究。***