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

为了提高刀具的耐磨性和耐热性，刀具已被成功地涂覆了一层薄的硬质层，从而延长了刀具寿命。除了成分和层结构(单层、组合、多层)外，与工艺相关的残余应力对所产生的刀具性能有最重要的影响。涂层条件的过程中变化使得能够具体地调整涂层和涂层-基材-化合物中的残余应力深度分布，以改善刀具性能。特别注意直接位于刀具刃口的高度弯曲的表面，因为在这里经常发生磨损起始。在该工具范围内，与平面相比，与工艺相关的沉积条件不同。用目前已应用的方法，不可能通过实验直接测定刀具刃口中的残余应力。拉曼光谱与X射线衍射法相结合，提供了用于必要的局部分辨测量的潜力。本项目的第一部分是用于测量普通(Ti，Al)N涂层残余应力的拉曼方法的制备。在第二部分中，有针对性地分析了刀具刃口残余应力与刀具磨损行为之间的关系。当了解了磨损产生的原因并给出了设计刃口残余应力的建议时，这个项目的目标就会达到。

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.