Reducing Chemical Wear of Single Crystal Diamond Tools Cutting Alloys

减少单晶金刚石工具切削合金的化学磨损

• 批准号: 1728554
• 负责人: Youxing Chen
• 金额: $ 32.77万
• 依托单位: University of North Carolina at Charlotte
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-10-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1728554&HistoricalAwards=false
• 关键词: Reducing; Chemical; Wear; Single; Crystal

Next-generation freeform optical components are often made from metal molds which themselves are cut on high quality machines using synthetic single crystal diamonds (SCD). Despite being the hardest known tool material, diamond wears surprisingly quickly when cutting some metals due to chemical interactions. This research will investigate aspects of those interactions, such as temperatures in cutting which are extremely difficult to measure at the length scale of the diamond/workpiece interaction. The temperatures can be predicted, using models with some embedded assumptions; methods developed for microsystems manufacturing will be used to deposit temperature sensors on the diamond tool surfaces and measure temperature distributions. These measurements will be used to validate the models. Chemical wear rate as a function of diamond orientation will be measured using specially manufactured tools and as a function of oxygen concentration by machining in a controlled-atmosphere chamber. Quantitative prediction of diamond wear rates could enable cost effective production of longer life optical molds in alloys not currently considered "diamond machinable". Such molds will enable manufacturing of next generation structured and freeform optical surfaces for applications ranging from energy efficient illumination to compact imaging systems for virtual reality, heads-up displays, and night vision. Improvements in the scientific understanding of diamond machining can positively impact a number of manufacturing sectors, including automotive, aerospace, consumer electronics and defense. Technology dissemination will be through publications, professional societies, industry consortia such as the NSF I/UCRC Center for Freeform Optics, and through educational activities. UNC Charlotte is a minority serving institution, and therefore outreach to underrepresented minorities for undergraduate and graduate research opportunities should be fruitful. Results will be integrated into graduate and undergraduate courses. In sophomore manufacturing, "cool" applications such as heads-up displays and future generations of virtual reality spark interest, while the example that the hardest material cannot cut one of the softest metals (cerium) helps keep the students engaged. This project will seek an improved fundamental understanding of the thermal, chemical and mechanical conditions leading to single crystal diamond tool wear during metal alloy machining, with the goal of allowing process improvement. Diamond tool tip temperatures are a significant factor in chemical tool wear, but they are notoriously difficult to measure during cutting. Validated thermal models are required. Validated temperatures will be used to determine activation energies for the chemical wear reaction using the Arrhenius equation, providing predictive understanding of tool wear under different conditions. The high thermal conductivity of diamond significantly affects modelled temperature distributions and should therefore affect the reaction rates. Synthetic diamonds are now being produced with thermal conductivities around 30% higher than previously available. Wear of tools made from diamonds with measured, different thermal conductivities will be tested by using diamonds sourced from different suppliers and produced through different means. The crystallographic orientation of a diamond affects mechanical wear and diamond etching rates by some molten metals. To determine the effect of diamond orientation on chemical wear, the wear rates for SCD tools of varying orientation when cutting reactive alloys will be tested. An environmental chamber enclosing a turning operation with a diamond tool will address the importance of oxygen on diamond wear. Freeform optics are the next revolution in optical capabilities. Their use in illumination improves energy efficiency and reduces light pollution. More compact, higher performance imaging systems enable smaller, lighter systems ranging from multispectral military systems to CubeSat missions. The scientific understanding of the manufacturing process developed here will enable an ever broadening range of cost effective applications. The results will be disseminated through industry interactions and publications/presentations at the Optical Society of America, SPIE (the international society for optics and photonics), the American Society for precision Engineering, and CIRP (The International Academy for Production Engineering). UNC Charlotte is dedicated to recruitment and retention of under-represented groups who will encounter the results of this research in undergraduate (Manufacturing Systems (core ME) and Metrology and Precision Engineering (elective)) and graduate classes (Introduction to Optical Fabrication and Testing, Advanced Surface Finish).

下一代自由曲面光学元件通常由金属模具制成，这些金属模具本身在高质量的机器上使用合成单晶金刚石（SCD）切割。尽管金刚石是已知最硬的工具材料，但由于化学相互作用，在切割某些金属时，金刚石的磨损速度惊人。本研究将调查这些相互作用的各个方面，例如切割中的温度，这些温度在金刚石/工件相互作用的长度尺度上非常难以测量。温度可以预测，使用模型与一些嵌入式假设;微系统制造开发的方法将用于存款温度传感器的金刚石工具表面和测量温度分布。这些测量将用于验证模型。化学磨损率作为金刚石取向的函数将使用专门制造的工具测量，并作为氧气浓度的函数，通过在可控气氛室中加工。金刚石磨损率的定量预测可以使成本有效地生产更长寿命的合金光学模具目前不被认为是“金刚石机加工”。这种模具将能够制造下一代结构化和自由形式的光学表面，用于从节能照明到用于虚拟现实、抬头显示器和夜视的紧凑型成像系统的应用。对金刚石加工的科学理解的提高可以对许多制造业产生积极影响，包括汽车，航空航天，消费电子和国防。技术传播将通过出版物，专业协会，行业联盟，如NSF I/UCRC自由光学中心，并通过教育活动。夏洛特夏洛特是一个少数民族服务机构，因此推广到代表性不足的少数民族的本科生和研究生的研究机会应该是富有成效的。结果将被纳入研究生和本科课程。 在大二的制造业中，平视显示器和未来几代虚拟现实等“酷”应用激发了学生的兴趣，而最硬的材料无法切割最软的金属（铈）的例子有助于保持学生的参与度。该项目将寻求对金属合金加工过程中导致单晶金刚石工具磨损的热，化学和机械条件的基本理解，以实现工艺改进的目标。金刚石工具尖端温度是化学工具磨损的一个重要因素，但众所周知，在切削过程中很难测量。需要经过验证的热模型。将使用经验证的温度，通过Arcidius方程确定化学磨损反应的活化能，从而提供对不同条件下刀具磨损的预测性理解。 金刚石的高导热性显著影响模拟的温度分布，因此应该影响反应速率。现在生产的合成金刚石的热导率比以前高出约30%。将使用来自不同供应商并通过不同方式生产的金刚石，测试由具有测量的不同热导率的金刚石制成的工具的磨损。金刚石的晶体取向影响机械磨损和金刚石被某些熔融金属蚀刻的速率。 为了确定金刚石取向对化学磨损的影响，将测试切削活性合金时不同取向的SCD工具的磨损率。一个环境室封闭的钻石工具车削操作将解决氧气对钻石磨损的重要性。 自由曲面光学是光学功能的下一次革命。它们在照明中的使用提高了能源效率并减少了光污染。更紧凑、更高性能的成像系统可以实现更小、更轻的系统，从多光谱军事系统到立方体卫星任务。对这里开发的制造工艺的科学理解将使成本效益的应用范围不断扩大。 研究结果将通过美国光学学会、SPIE（国际光学与光子学会）、美国精密工程学会和CIRP（国际生产工程学会）的行业互动和出版物/演示文稿进行传播。夏洛特夏洛特致力于招聘和保留代表性不足的群体，他们将在本科（制造系统（核心ME）和计量与精密工程（选修））和研究生课程（光学制造和测试介绍，高级表面光洁度）中遇到这项研究的结果。

项目成果

Deformation mechanisms in single crystal Ni-based concentrated solid solution alloys by nanoindentation

• DOI: 10.1016/j.msea.2022.143685
• 发表时间: 2022-08
• 期刊: Materials Science and Engineering: A
• 作者: Liuqing Yang;Youxing Chen;Jimmie A. Miller;W. J. Weber;H. Bei;Yanwen Zhang