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刀具的纳米晶体金刚石涂层的行为，使干式加工变得经济。将研究常规尺寸的工具和新的微尺度工具，小到人头发的宽度。研究方法包括生长极薄的金刚石涂层，测量其摩擦性能，预测其对切割温度的影响，并在干法加工与工业相关的铝合金时对其进行评估。金刚石生长过程将被量身定做，以重复地生产厚度小于1微米的均匀金刚石薄膜，具有纳米尺寸的颗粒，并与碳化钨刀具材料有很强的粘附性。利用原子力显微镜、环境控制摩擦计量学、空间分辨表面光谱和正交加工实验，从纳米到宏观的尺度研究金刚石薄膜的摩擦、磨损和结构特性。这将决定生长参数和由此产生的涂层性能之间的关系。对纳米金刚石的低摩擦系数所带来的刀具温度降低进行了模拟。针对一种广泛应用于交通运输行业的高硅铸造铝合金的钻削和微端铣削，将对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这一尚未解决的重大工业问题而造福社会。减少或取消在干式加工软、研磨金属时使用金属加工液，将同时减少对环境的影响和制造业的能源消耗，从而提高经济竞争力。纳米晶金刚石涂层因其高硬度、低摩擦系数和与工件材料的低附着力而极具前景，从而分别减少了磨损、发热和切屑堵塞。培养工科学生，招收和留住代表不足的群体的学生，并指导他们攻读研究生课程，将产生进一步的社会影响。这包括一个历史上代表性不足的群体中的一名学生，他将得到这个项目的支持。将开发公共宣传演示，以培养初中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，并使学生接触到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.