Einfluss von unterschiedlich erzeugten Verschleißschutzschichten auf das Dauerschwingverhalten ausgewählter Werkstoffe und deren Verbesserung

一般来说，磨损损伤的进展可以很好地估计，叠加的机械载荷和高温可能对涂层部件的寿命产生灾难性的影响。例如，高循环轴承压力可由滚动力引起。与此同时，剪切应力的最大值位于表面以下几毫米处。由于这些压缩和剪切应力的循环性质，耐磨涂层需要设计和测试高循环疲劳性能。此外，还必须考虑温度的影响。摩擦学系统需要具有合适微观结构的表面，这些微观结构可以在高温下实现高耐磨性和抗疲劳性。决定寿命的其他因素是所施加工作载荷的性质和大小。在轴向载荷或弯曲载荷下，各个涂层系统的行为必须通过在准静态和循环载荷下作为温度的函数进行系列试验来研究。还必须分析基体/涂层或基体/硬质合金相之间界面形态的程度。该项目将包括保护基体免受干磨粒磨损的MMC涂层。颗粒增强铁、镍、钴基合金可提高耐磨性。磨损保护通过嵌入相对软的基质中并垂直对准表面的合适几何形状的硬金属颗粒来实现。然而，这种特殊的结构形态可能会间接影响裂纹成核和裂纹扩展。在高压载荷下，硬质相和硬质相与基体之间的界面可能成为裂纹成核位置。将研究在何种程度上会发生这种疲劳过程以及在何种程度上会导致多层系统的过早失效。在剧烈磨损的情况下，基体必须足够坚固，以支撑嵌入的硬质合金颗粒抵抗所施加的力，并防止涂层的脆性失效。将进行热处理以优化耐磨性和抗疲劳性。这一目标可以通过细分散碳化物的沉淀而进行二次硬化来实现。精确调整的热处理可以提高基体的强度，从而提高疲劳强度，但也可以改善嵌入硬质合金颗粒的支撑性。然而，强度的提高往往会导致延展性的损失。本项目的研究活动旨在以优化磨损和HCF性能的方式将材料和材料系统特性联合收割机结合起来。所需的热处理必须考虑到基体的微观结构变化。为了在这些承受磨损和疲劳载荷的部件的制造中实现经济的工艺，必须详细说明集成的工艺步骤。

Whereas in general, the progress of wear damage can be quite well estimated, superposed mechanical loading and high temperatures can have catastrophic effects on the life time of coated components. For example, high cyclic bearing pressures can result from rolling forces. At the same time, shear stresses are induced with maximum values located some millimeters below the surface. Because of the cyclic nature of these compressive and shear stresses, the wear resistant coatings need to be designed and tested with regard to high cycle fatigue performance. In addition, the influence of temperature has to be taken into account. Tribological systems require surfaces with suitable microstructures that can achieve both high wear and fatigue resistances at high temperatures. Further life-determining factors are the nature and magnitude of the applied service loads. How the individual coating systems behave under axial or bending loads must be investigated by test series under quasi-static and cyclic loading as a function of temperature. The degree to which the interface morphology between substrate/coating or matrix/hardmetal phase must also be analyzed.This project will include MMC coatings that protect the substrate against dry abrasive wear. The abrasive wear resistance will be enhanced by particle reinforced Fe, Ni and Co base alloys. The wear protection is realized by hard metal particles of suitable geometry being embedded in the relatively soft matrix and vertically aligned to the surface. However, this particular structural morphology may detrimentally affect crack nucleation and crack propagation. At high pressure loads, the hard phases and the interfaces between the hard phase and the matrix may become crack nucleation sites. To what extent such fatigue progress may occur and to what extent this may contribute to premature failure of the multilayer system will be investigate.In case of intensive wear situations, the matrix must be strong enough to support the embedded hardmetal particles against the applied forces and to prevent brittle failure of the coating. Heat treatments will be performed for optimizing wear and fatigue resistances. This target can be realized by secondary hardening due to the precipitation of finely dispersed carbides. A precisely tuned heat treatment increases the strength of the matrix and thereby also the fatigue strength but in addition, can lead to an improved support of the embedded hardmetal particles.The increase in strength, however, often results in a loss of ductility. The research activities in this project aim to combine the material and material system properties in such a way that wear as well as HCF performance are optimized. The required heat treatments must take into account the microstructure changes of the substrate. In order to realize economic processes in the manufacturing of these components that are subjected to wear and fatigue loading, integrative process steps must be elaborated.