Collaborative Research: Multi-Scale Experiments and Modeling of Nanocrystalline Diamond Coatings for Dry Machining

该合作研究奖的目标是可靠地发展和了解用于切削工具的纳米晶体金刚石涂层的行为，这将使干式加工经济。传统尺寸的工具和新颖的微型工具，小如人类头发的宽度，将被研究。研究方法包括生长极薄的金刚石涂层，测量其摩擦性能，预测其对切削温度的影响，以及在干式加工工业相关铝合金时对其进行评估。金刚石生长过程将被量身定制，以重复生产均匀的金刚石膜，厚度小于1微米，具有纳米尺寸的颗粒，并与碳化钨刀具材料具有很强的附着力。利用原子力显微镜、环境控制摩擦测量、空间分辨表面光谱学和正交加工实验，从纳米到宏观尺度研究金刚石膜的摩擦、磨损和结构特性。这将决定生长参数和最终涂层性能之间的关系。模拟了纳米晶金刚石的低摩擦系数所带来的刀具温度降低。将对一种广泛应用于运输行业的高硅含量铸铝合金的钻孔和微端铣削涂层刀具的干式加工性能进行评估。这项研究将通过解决金属加工液的主要、未解决的工业问题而造福社会。减少或消除金属加工液在软磨料金属干式加工中的使用，将同时减少制造业的环境影响和能源消耗，从而提高经济竞争力。纳米晶金刚石涂层由于其高硬度、低摩擦系数和对工件材料的低粘附性，从而分别减少磨损、产生热量和切屑堵塞，因此极有前景。进一步的社会影响将来自培训工程专业的学生，从代表性不足的群体中招募和留住学生，并指导他们攻读研究生课程。其中包括一名来自历史上代表性不足的群体的学生，他将得到这个项目的支持。为了培养初高中学生对科学和工程的兴趣，将开展公众宣传演讲。大学、工业和政府实验室之间的密切合作将促进技术转让，并使学生获得更多样化的教育体验。

The objectives of this collaborative research award are to reliably grow and understand the behavior of nano-crystalline diamond coatings for cutting tools that will make dry machining economical. Tools of conventional sizes and novel micro-scale tools, as small as the width of a human hair, will be studied. The research approach involves growing extremely thin diamond coatings, measuring their friction properties, predicting their impact on cutting temperature, and evaluating them when dry machining an industrially-relevant aluminum alloy. The diamond growth process will be tailored to repeatably produce uniform diamond films, less than one-micrometer thick, with nanometer size grains, and strong adhesion to the tungsten carbide tool material. The friction, wear, and structural properties of the diamond films will be studied at from the nano- to macro-scale using atomic force microscopy, environmentally-controlled tribometry, spatially-resolved surface spectroscopy, and orthogonal machining experiments. This will determine the relationship between growth parameters and resulting coating properties. The cutting tool temperature reduction afforded by the low friction coefficient of the nano-crystalline diamond will be modeled. Dry machining performance of coated tools will be evaluated for drilling and micro end milling of a cast aluminum alloy with high silicon content that is used extensively in the transportation industry. This research will benefit society by addressing the major, unsolved industrial problem of metalworking fluids. Reducing or eliminating the use of metalworking fluids in dry machining of soft, abrasive metals, will simultaneously reduce the environmental impact and energy consumption of the manufacturing industry, resulting in improved economic competitiveness. Nano-crystalline diamond coatings are extremely promising because of their high hardness, low coefficient of friction, and low adhesion to workpiece material thus reducing wear, heat generation, and chip clogging, respectively. Further societal impact will result from training engineering students, recruiting and retaining students from underrepresented groups, and guiding them to graduate programs. This includes one student from a historically underrepresented group who will be supported by this project. Public outreach presentations will be developed to foster an interest in science and engineering among middle and high school students. The close collaboration between the universities, industry, and government lab will enhance technology transfer and expose the students to a more diverse educational experience.