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生长和了解用于切削工具的纳米晶金刚石涂层的行为，从而使干式加工变得经济。 将研究常规尺寸的工具和小至人类头发宽度的新型微型工具。研究方法包括生长极薄的金刚石涂层，测量其摩擦特性，预测其对切削温度的影响，并在干加工工业相关铝合金时对其进行评估。 金刚石生长工艺将经过定制，可重复生产均匀的金刚石薄膜，厚度小于一微米，具有纳米尺寸的晶粒，并对碳化钨刀具材料具有很强的附着力。 将利用原子力显微镜、环境控制摩擦测量、空间分辨表面光谱和正交加工实验，从纳米到宏观尺度研究金刚石薄膜的摩擦、磨损和结构特性。 这将确定生长参数和所得涂层性能之间的关系。 纳米晶金刚石的低摩擦系数所带来的切削工具温度降低将被建模。 将评估涂层刀具的干式加工性能，用于对运输行业广泛使用的高硅含量铸造铝合金进行钻孔和微端铣。 这项研究将通过解决金属加工液这一尚未解决的主要工业问题来造福社会。 在软质、磨蚀性金属的干式加工中减少或消除金属加工液的使用，将同时减少制造业对环境的影响和能源消耗，从而提高经济竞争力。 纳米晶金刚石涂层因其高硬度、低摩擦系数和对工件材料的低粘附力而非常有前途，从而分别减少磨损、发热和切屑堵塞。 进一步的社会影响将来自培训工程专业学生、招募和留住代表性不足群体的学生以及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群体的学生，他将受到该项目的支持。 将开展公共宣传演讲，以培养中学生对科学和工程的兴趣。 大学、行业和政府实验室之间的密切合作将加强技术转让，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.