Effects of cutting edge residual stresses on the wear behavior of PVD-coated cutting tools

切削刀具已成功地涂覆有薄的硬质层，以改善其磨损和热性能，从而延长刀具寿命。除了成分和层结构（单层、组合层、多层）外，与工艺相关的残余应力对最终的工具性能具有最重要的影响。涂层条件的过程中变化使得能够分别对涂层和涂层-基材-化合物中的残余应力深度分布进行特定调节，用于改善工具性能。特别注意的是直接在切削刃的高度弯曲的表面，因为这里经常发生磨损。在该工具范围内，与平坦表面相比，与工艺相关的不同沉积条件占主导地位。用目前应用的方法不可能直接在切削刃上用实验测定残余应力。拉曼光谱提供了潜力，在与X射线衍射法相结合，被应用于必要的本地解决的测量。本计画的第一部分是准备拉曼法来量测一般（Ti，Al）N涂层的残余应力。第二部分有针对性地分析了切削刃残余应力与刀具磨损行为的关系。当磨损的原因已经被理解并且可以给出切削刃残余应力设计的建议时，这个项目的目标将被达到。

Cutting tools have successfully been coated with thin hard layers in order to improve their wear and thermal properties for longer tool life. Apart from composition and layer structure (single, combined, multi layer), the process related residual stresses have the most important effects on resulting tool properties. An in-process variation of the coating conditions enables a specific adjustment of residual stress depth distributions in coating and coating-substrate-compound, resp., for an improved tool behaviour. Particular attention is paid to the highly curved surface directly in the cutting edge, as here frequently wear initiation takes place. In this tool range process related different deposition conditions prevail than on flat surfaces. An experimental determination of residual stresses directly in the cutting edge is not possible with the so far applied methods. Raman spectroscopy offers the potential, in a combination with X-ray diffractometric methods, to be applied for the necessary locally resolved measurements. The first part of this project deals with the preparation of the Raman method for residual stress measurement at common (Ti,Al)N coatings. In the second part targetedly relations between cutting edge residual stresses and wear behavior of the tools will be analyzed. The goal of this project will be reached, when the causes of wear initiation have been understood and recommendations for a design of cutting edge residual stresses can be given.