A Fundamental Study on Gas Film Formation and its Effect in Electrochemical Discharge Machining Process

先进的工程材料和合金具有优异的物理性能。然而，由于这些材料的硬度、脆性等特点，传统的加工方法很难加工，导致刀具磨损和表面损伤增加。该奖项支持对电化学放电加工(ECDM)的基础研究，这是一种非传统工艺，可提高对美国经济和国家安全至关重要的先进工程材料的表面完整性。采用建模、模拟和实验相结合的方法，对先进材料ECDM中气膜的形成和稳定性进行了研究。随后将分析已加工表面的表面形貌、机械性能和摩擦学性能以及成分。各种导电和非导电材料可加工性的预期改善将有助于释放这些材料在生物医学、电子、汽车和能源行业的全部应用潜力。这些行业的潜在应用包括髋关节假体、电子封装、刹车衬片和固体氧化物燃料电池。本研究的多学科方法和结果可推广到其他电加工工艺中。该项目的成果将纳入研究生和本科课程，以及在女性和代表性不足的少数群体中的培训和学习。这项研究的结果将通过同行评议的出版物、专业学会会议上的演讲和YouTube视频进行传播。通过这项研究，将通过进行分析和实验研究来了解气膜厚度和稳定性对加工零件表面完整性变化的影响，从而获得关于电化学放电加工过程中气膜形成和稳定性的基本知识。分子动力学模拟将获得对气泡形成速率、聚结速率和气膜厚度的重要了解，以产生稳定而薄的气膜。ECDM的电学、化学和热学耦合有限元模拟将被用来研究气膜形成过程中边界层的流体动力学行为。基于多种物理的数学模型将被用来预测ECDM中的气膜厚度、放电能量和表面粗糙度。光电反馈信号的传感器融合将用于实验研究过程中的监测和控制。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Advanced engineering materials and alloys possess excellent physical properties. However, machining these materials by traditional methods is difficult due to their hardness, brittleness, and other characteristics, leading to increased tool wear and surface damage. This award supports a fundamental study of electrochemical discharge machining (ECDM) - a nontraditional process that improves the surface integrity of advanced engineering materials that are critical for the US economy and national security. Using modeling, simulation and experimental methods, the formation and stability of gas film in the ECDM of advanced materials will be studied. The topography, mechanical and tribological properties, and composition of the machined surface will be analyzed subsequently. The expected improvement in the machinability of a wide variety of both conductive and nonconductive materials will help in unleashing the full application potential of these materials in biomedical, electronic, automotive, and energy industries. Potential applications in these industries include hip joint prosthesis, electronics packaging, brake linings, and solid oxide fuel cells. The multi-disciplinary approach and results of this study can be extended to other electrical machining processes. The outcome of this project will be integrated into graduate and undergraduate courses, and training and learning within female and underrepresented minorities. The results of this research will be disseminated through peer-reviewed publications, presentations at professional society meetings, and YouTube videos.Through this research, fundamental knowledge on the mechanism of gas film formation and stability during the electrochemical discharge machining process will be generated by conducting analytical and experimental investigations to understand the effect of thickness and stability of the gas film on the surface integrity changes in machined parts. Critical insight into the rate of gas bubble formation, the rate of coalescence, and the gas film thickness will be acquired by molecular dynamics simulations to produce stable and thin gas film. Finite element simulations coupling electrical, chemical and thermal aspects of ECDM will be pursued to investigate the hydrodynamic behavior of boundary layers during gas film formation. Multi-physics based mathematical models will be developed to predict the gas film thickness, discharge energy and surface roughness in ECDM. Sensor fusion of optical and electrical feedback signals will be used in the experimental studies for in-process monitoring and control.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.