Theory of chip formation in grinding of biphasic brittle materials using the example of WC-Co carbide

WC-Co硬质合金的相组成和WC晶粒尺寸分布显著影响其材料性能，如硬度H、杨氏模量E和临界断裂韧性KIc。此外，在第一个研究期间，已证明硬质合金规格显著影响材料去除行为，因此也影响硬质合金工件的质量。除了高工件质量外，硬质合金的磨削还必须满足经济性要求。成本驱动因素是磨削工具磨损。必须假定硬质合金规格对磨具磨损有决定性影响。目前还不清楚相分数和WC粒度分布如何影响磨削工具磨损。因此，该研究项目的目的是描述和解释模型的工具磨损作为功能的WC-Co硬质合金规格在磨削。为了研究其磨损机理，进行了单磨粒切削试验。通过对划痕的分析，可以研究颗粒的定量磨损。通过扫描电子显微镜和透射电子显微镜对颗粒进行定性分析，还可以识别磨损机制。然后进行磨削试验，以检查砂轮磨损，并检查单颗粒切削试验结果的可移植性。最后，建立了磨削WC-Co硬质合金时刀具磨损的定性描述和解释模型。

The phase fractions and the WC grain size distribution of WC-Co cemented carbides significantly influence their material properties such as, the hardness H, the Youngs modulus E and the critical fracture toughness KIc. Furthermore, during the first research period it was proven that the cemented carbide specification significantly influences the material removal behavior and consequently also the quality of the workpieces of the cemented carbides. In addition to high workpiece quality, grinding of cemented carbides has to meet economical requirements as well. A cost driver is the grinding tool wear. It must be assumed that the cemented carbide specification has a decisive influence on the grinding tool wear. Currently it is unknown how the phase fractions and the WC grain size distribution affects the grinding tool wear. Therefore, the aim of the research project is a description and an explanation model for the tool wear as a function of the WC-Co cemented carbide specification in grinding. For the investigation of the wear mechanisms, single grain cutting tests are carried out. By an analysis of the scratch tracks, the quantitative wear of the grains can be investigated. The qualitative analysis of the grains by means of scanning electron and transmission electron microscopy additionally enables the identification of the wear mechanisms. Grinding tests are then carried out in order to examine the grinding wheel wear and to check the transferability of the findings from the single grain cutting tests. Finally, a qualitative description and explanation model for grinding tool wear in grinding of WC-Co carbides is developed.