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，金属模具本身是使用合成单晶金刚石 (SCD) 在高质量机器上切割而成。尽管金刚石是已知最硬的工具材料，但在切割某些金属时，由于化学相互作用，金刚石的磨损速度惊人地快。这项研究将调查这些相互作用的各个方面，例如切割时的温度，这在金刚石/工件相互作用的长度尺度上很难测量。可以使用带有一些嵌入假设的模型来预测温度；为微系统制造开发的方法将用于在金刚石工具表面沉积温度传感器并测量温度分布。这些测量结果将用于验证模型。化学磨损率与金刚石取向的函数关系将使用专门制造的工具进行测量，而化学磨损率与氧浓度的函数关系则通过在受控气氛室中进行加工来测量。金刚石磨损率的定量预测可以使使用目前不被认为是“金刚石可加工”的合金来经济有效地生产寿命更长的光学模具。此类模具将能够制造下一代结构化和自由形状光学表面，其应用范围从节能照明到虚拟现实、平视显示器和夜视的紧凑成像系统。提高对金刚石加工的科学认识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（例如 NSF I/UCRC 自由曲面光学中心）以及教育活动进行。北卡罗来纳大学夏洛特分校是一所少数族裔服务机构，因此向代表性不足的少数族裔提供本科和研究生研究机会应该会取得成果。结果将纳入研究生和本科生课程。 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之一（铈）的例子有助于保持学生的参与度。该项目将寻求更好地了解金属合金加工过程中导致单晶金刚石刀具磨损的热、化学和机械条件，目的是改进工艺。金刚石刀尖温度是化学刀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它们。需要经过验证的热模型。经验证的温度将用于使用阿伦尼乌斯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了解。 金刚石的高导热性显着影响模拟的温度分布，因此应该影响反应速率。现在生产的人造金刚石的导热率比以前高出约 30%。将使用来自不同供应商并通过不同方式生产的钻石来测试具有不同热导率的金刚石制成的工具的磨损情况。金刚石的晶体取向会影响某些熔融金属的机械磨损和金刚石蚀刻速率。 为了确定金刚石取向对化学磨损的影响，将测试切割活性合金时不同取向的 SCD 刀具的磨损率。封闭使用金刚石刀具进行车削操作的环境室将解决氧气对金刚石磨损的重要性。 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实现从多光谱军事系统到立方体卫星任务的更小、更轻的系统。对这里开发的制造工艺的科学理解将使得具有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（国际光学与光子学学会）、美国精密工程学会和 CIRP（国际生产工程学院）的行业互动和出版物/演示来传播。北卡罗来纳大学夏洛特分校致力于招募和留住代表性不足的群体，他们将在本科生课程（制造系统（核心 ME）和计量与精密工程（选修））和研究生课程（光学制造和测试概论、高级表面处理）。

项目成果

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

纳米压痕法研究单晶镍基浓固溶体合金的变形机制

• DOI: 10.1016/j.msea.2022.143685
• 发表时间: 2022-08-01
• 期刊: Materials Science and Engineering: A
• 作者: Liuqing Yang;Youxing Chen;Jimmie A. Miller;W. J. Weber;H. Bei;Yanwen Zhang
• 通讯作者: Yanwen Zhang