Effects of Heterogeneity, Anisotropy and Length Scale Effects in Microscale Deformation Processes

微尺度变形过程中非均质性、各向异性和长度尺度效应的影响

• 批准号: 0500239
• 负责人: Jeffrey Kysar
• 金额: --
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0500239&HistoricalAwards=false
• 关键词: Effects; Heterogeneity; Anisotropy; Length; Scale

The objectives of the proposed research are to systematically and individually study the effects of anisotropy, heterogeneity and length scale effects in microscale material deformation processes which are encountered in microscale manufacturing. While the techniques to be employed in this research could be applied to any microscale manufacturing process, the PIs will focus efforts Micro Laser Peen Forming (mLPF). The approach is to experimentally characterize materials subjected to mLSP and mLPF processes by measuring the induced residual stresses with microscale x-ray diffraction techniques, by measuring the distributions and degrees of plastic deformation with Electron Backscatter Diffraction (EBSD), and also to measure the final shape of the deformed specimens using various commercial techniques. In order to isolate the effects of anisotropy the processes will be performed on single crystals. To isolate the effects of heterogeneity, the processes will be performed near the grain boundary of a bicrystal. Potential length scale effects of the plastic deformation will be probed with electron backscatter diffraction (EBSD) which allows estimates of the density of geometrically necessary dislocations. The two processes will be numerically simulated using the finite element technique, taking into account rate effects, hardening effects, the anisotropic, heterogeneous nature of the material, and will incorporate length scale effects if deemed necessary by the experimental results.Expected results will help micro manufacturing processes to make higher quality micro components. The significantly improved understanding of process capability and limitations will open up opportunities for new micro part designs. Personnel development and dissemination of results will improve national competitiveness in micro manufacturing. A significant effort will be made to involve students from traditionally underrepresented backgrounds in the research.

本研究的目的是系统地、个别地研究在微尺度制造中所遇到的微尺度材料变形过程中各向异性、非均质性和长度尺度效应的影响。虽然这项研究中使用的技术可以应用于任何微尺度的制造工艺，但PI将专注于微激光喷丸成形(MLPF)。该方法是通过用微尺度X射线衍射技术测量诱发残余应力，用电子背散射衍射(EBSD)测量塑性变形的分布和程度，以及用各种商业技术测量变形样品的最终形状，来实验表征经历MLSP和mLPF工艺的材料。为了隔离各向异性的影响，这些过程将在单晶上进行。为了分离异质性的影响，这些过程将在双晶的晶界附近进行。塑性变形的潜在长度尺度效应将用电子背散射衍射(EBSD)来探测，它可以估计几何上必要的位错密度。这两个过程将使用有限元技术进行数值模拟，考虑了速率效应、硬化效应、材料的各向异性和非均质性，如果实验结果认为有必要，还将考虑长度尺度效应。预期的结果将有助于微制造工艺制造更高质量的微部件。对工艺能力和限制的理解的显著提高将为新的微型部件设计打开机会。人才开发和成果传播将提高国家在微制造方面的竞争力。将做出重大努力，让来自传统上代表性不足的背景的学生参与研究。