Measuring Thermomechanical Material Response During Micromachining by In Situ Scanning Electron Microscopy

本研究的目的是利用原位扫描电子显微镜来阐明微细加工中切屑形成的变形机理。在这项研究中，金属切割将在扫描电子显微镜样品室内的定制子工作台上进行，其配置能够以二次和背散射电子成像模式直接可视化和表征变形区。随后，将通过对微加工过程的二次电子显微图像序列的数字图像相关来原位描绘变形机理。将使用电子背散射衍射技术研究微米级表面产生的微观结构后果。如果成功，这项研究可能显著提高当前对微机械加工过程的理解水平，并可能取代现有的实验范例，这些实验范例最多提供的是完全不包含操作微观机构动态细节的后变形、异地方案。可以预见，这项研究固有的跨学科框架可以通过将真空设备设计、定量电子显微镜以及计算图像处理方法的元素结合在一起，为研究生的多方面发展提供独特的机会。预计将通过整合现有的制造课程和为工业、机械和材料科学学科的大四和大三学生开设一门新课程，对推进本科教育产生影响。

The objective of this research is to elucidate the deformation mechanics of chip formation in micromachining using in situ scanning electron microscopy. In this study, metal cutting will be performed on a customized sub-stage within the sample chamber of a scanning electron microscope in a configuration that enables direct visualization and characterization of the deformation zone in secondary and backscattered electron imaging modes. Subsequently, the mechanics of deformation will be delineated in situ through digital image correlation of sequences of secondary electron micrographs of the micromachining process. The microstructural consequences of micrometer-scale surface generation will be studied using electron backscattered diffraction techniques. Together, these characterizations can enable a detailed demarcation of the thermomechanical material response during material removal at small length-scales.If successful, this research may significantly enhance the current level of understanding of the micromachining process and possibly supplant the extant experimental paradigms which offer at best, a post-deformation, ex situ scheme entirely devoid of the dynamic details of the operative micromechanisms. It is envisioned that the interdisciplinary framework inherent to this research may offer unique opportunities for multi-faceted development of graduate students by bringing together elements of vacuum device design, quantitative electron microscopy as well as computational image processing methodologies. An impact on advancing undergraduate education is envisaged via integration with existing courses in manufacturing and creation of a new course aimed at seniors and juniors in the Industrial, Mechanical and Materials Science disciplines.