Laser Surface Textured Cemented Carbides for Application in Abrasive Machining Processes

磨料刀具的切削效率与刀具表面凸出的磨粒所产生的内在表面形貌直接相关。该项目的基本概念继承于磨料加工过程中单个磨料颗粒行为的研究。然而，要排除其他邻近磨粒对相关切削表面的影响并不容易。因此，设想一种在刀具切削表面隔离或制造单晶粒的方法具有重要意义。在这方面，可以建议使用更传统的硬质材料，如硬质合金，作为昂贵刀具材料的替代品，只要现有磨具的表面形貌特征可以在相应的长度尺度上复制，并且力学性能也可以满足这种切削要求。在之前对磨具（以CBN珩磨石为例）的研究中，对切削表面的地形特征，特别是突出颗粒的几何形状和分布进行了统计表征。新型硬质合金刀具的表面形貌将在前人研究成果的基础上进行构思和设计。随后，这些几何特征将使用先进的激光表面纹理（LST）技术复制到硬质合金上。以往激光物质反应机理的基础研究成果是LST工艺设计、获得高几何精度、提高表面完整性和避免表面损伤的基础。然后，通过涂层技术提高这些新型刀具的力学性能。应研究和改进涂层在激光加工表面上的相容性。最后，新工具的性能将通过各种实现进行验证，并与传统磨具进行比较，包括切削测试、摩擦学测试和机械性能研究。

Cutting effectiveness of abrasive tools is directly related to their intrinsic surface topography resulting from the abrasive grains protruding out of the tool surfaces. The fundamental concept of this project inherits from the study of the behavior of single abrasive grains in the abrasive machining processes. However, it is not easy to exclude the influences of other adjacent abrasive grains on the associated cutting surfaces. Therefore, it is meaningful to conceive an approach to isolate or fabricate single grains on the tool cutting surface. In this regard, the use of more conventional hard materials, e.g. cemented carbide, might be proposed as alternative for expensive tool materials, as long as the surface topography features of current abrasive tools can be replicated at the corresponding length scales and the mechanical properties can also meet such cutting requirements. In a previous study of abrasive tools (CBN honing stone as example), topographical features of the cutting surfaces, especially the geometry and distributions of the protruding grains were statistically characterized. Surface topography of the novel cemented carbide tools will be conceived and designed based on the results of the previous study. Subsequently, these geometrical features will be replicated on cemented carbides using the advanced laser surface texturing (LST) technology. Results of previous fundamental research of laser-matter reaction mechanism are the base for LST process design, to obtain high geometrical precision, to improve surface integrity and to avoid surface damage. Afterwards, mechanical properties of these novel tools shall be enhanced through coating technology. The compatibility of the coatings on the laser machined surfaces shall be studied and improved. Finally, performance of the new tools will be validated and compared with traditional abrasive tools by various implementations, including cutting tests, tribological tests and investigations of mechanical properties.