Collaborative Research: Deformation Phenomena in Surface Texturing by Machining-Based Processes

这个合作研究项目的目标是建立基本原理，将基于加工的过程产生的纹理表面的微观结构和微观尺度机械性能与可控的过程变量联系起来。为了实现这一目标，一项实验研究将描述在变形过程中材料去除过程中普遍存在的应变、应变速率、温度等热机械变形条件及其对表面完整性的影响。将使用高速成像和图像相关等技术进行变形分析，以及先进的电子显微镜方法和纳米压痕进行微观结构分析。实验将辅以材料去除的力学建模，以估计加工变形过程中发生的瞬态塑性变形。通过整合这些结果，最终可以预测变形的性质，补充更好地理解表面纹理的几何地形方面。如果成功，研究结果的广泛影响将是通过设计和创造新的表面纹理来改善结构部件的性能和寿命。根据本文建立的原则，本设计将同时考虑形貌和表面完整性属性，如变形和微观结构。该研究将为表征多种长度尺度下的变形和微观结构提供实验和分析工具，使人们能够理解表面纹理力学和表面完整性之间的相互作用。这样的理解对于表征织构对结构部件（如轴承、泵和柴油燃料子系统）性能的影响是必不可少的。现象学见解将获得在加工和磨损过程中材料去除的瞬态变形现象。利用瞬态变形现象作为减少加工过程中能量耗散的手段，将有可能出现机会。

The objective of this collaborative research project is to establish the fundamental principles that relate microstructure and micro-scale mechanical properties of textured surfaces created by machining-based processes to the controllable process variables. To accomplish this, an experimental study will characterize thermo-mechanical deformation conditions of strain, strain rate, temperature, that prevail during material removal in texturing and their effects on surface integrity. Techniques such as high-speed imaging and image correlation for deformation analysis, and advanced electron microscopy methods and nano-indentation for microstructure analysis, will be used. The experiments will be complemented by modeling of mechanics of material removal to estimate the transient plastic deformation that occurs in texturing by machining. By integrating these results, the nature of the deformation can eventually be predicted, complementing the much better understood geometric-topographic aspects of surface texture.If successful, the broader impact of the results will be improved performance and life of structural components through design and creation of novel surface textures. Based on the principles established herein, this design will incorporate both topography and surface integrity attributes, such as deformation and microstructure. The research will provide experimental and analytical tools for characterizing deformation and microstructure at multiple length scales, enabling among other things, understanding of the interplay between mechanics of surface texturing and surface integrity. Such an understanding is essential for characterizing the effects of texture on performance of structural components such as bearings, pumps, and diesel fuel sub-systems. Phenomenological insights will be obtained into transient deformation phenomena underlying material removal in machining and wear processes. Opportunities will likely emerge for exploiting the transient deformation phenomena as a means for reducing energy dissipation in machining processes.