Xiang Junfeng, Pang Siqin, Xie Lijing, Gao Feinong, Hu Xin, Yi Jie, Hu Fang
School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Key Laboratory of Advanced Machining, Beijing Institute of Technology, Beijing 100081, China.
Materials (Basel). 2018 Feb 7;11(2):252. doi: 10.3390/ma11020252.
The aim of this work is to analyze the micro mechanisms underlying the wear of macroscale tools during diamond machining of SiC/Al6063 composites and to develop the mechanism-based diamond wear model in relation to the dominant wear behaviors. During drilling, high volume fraction SiC/Al6063 composites containing Cu, the dominant wear mechanisms of diamond tool involve thermodynamically activated physicochemical wear due to diamond-graphite transformation catalyzed by Cu in air atmosphere and mechanically driven abrasive wear due to high-frequency scrape of hard SiC reinforcement on tool surface. An analytical diamond wear model, coupling Usui abrasive wear model and Arrhenius extended graphitization wear model was proposed and implemented through a user-defined subroutine for tool wear estimates. Tool wear estimate in diamond drilling of SiC/Al6063 composites was achieved by incorporating the combined abrasive-chemical tool wear subroutine into the coupled thermomechanical FE model of 3D drilling. The developed drilling FE model for reproducing diamond tool wear was validated for feasibility and reliability by comparing numerically simulated tool wear morphology and experimentally observed results after drilling a hole using brazed polycrystalline diamond (PCD) and chemical vapor deposition (CVD) diamond coated tools. A fairly good agreement of experimental and simulated results in cutting forces, chip and tool wear morphologies demonstrates that the developed 3D drilling FE model, combined with a subroutine for diamond tool wear estimate can provide a more accurate analysis not only in cutting forces and chip shape but also in tool wear behavior during drilling SiC/Al6063 composites. Once validated and calibrated, the developed diamond tool wear model in conjunction with other machining FE models can be easily extended to the investigation of tool wear evolution with various diamond tool geometries and other machining processes in cutting different workpiece materials.
这项工作的目的是分析在SiC/Al6063复合材料的金刚石加工过程中宏观刀具磨损的微观机制，并建立与主要磨损行为相关的基于机制的金刚石磨损模型。在钻孔过程中，对于含铜的高体积分数SiC/Al6063复合材料，金刚石刀具的主要磨损机制包括在空气气氛中由铜催化的金刚石-石墨转变引起的热力学激活的物理化学磨损，以及由于硬SiC增强相在刀具表面高频刮擦而导致的机械驱动磨料磨损。提出了一种将臼井磨料磨损模型和阿累尼乌斯扩展石墨化磨损模型相结合的解析金刚石磨损模型，并通过用户定义子例程实现刀具磨损估计。通过将磨料-化学复合刀具磨损子例程纳入三维钻孔的耦合热-机械有限元模型，实现了SiC/Al6063复合材料金刚石钻孔过程中的刀具磨损估计。通过比较使用钎焊聚晶金刚石（PCD）和化学气相沉积（CVD）金刚石涂层刀具钻孔后的数值模拟刀具磨损形态和实验观察结果，验证了所开发的用于再现金刚石刀具磨损的钻孔有限元模型的可行性和可靠性。切削力、切屑和刀具磨损形态的实验结果与模拟结果相当吻合，表明所开发的三维钻孔有限元模型与金刚石刀具磨损估计子例程相结合，不仅可以在切削力和切屑形状方面，而且可以在SiC/Al6063复合材料钻孔过程中的刀具磨损行为方面提供更准确的分析。一旦经过验证和校准，所开发的金刚石刀具磨损模型与其他加工有限元模型相结合，就可以很容易地扩展到研究不同金刚石刀具几何形状和其他加工过程在切削不同工件材料时刀具磨损的演变。
