Investigations regarding a novel combination treatment of electron beam alloying and diamond-like carbon coating for highly stressed Al alloys

高应力铝合金电子束合金化和类金刚石碳涂层新型组合处理的研究

• 批准号: 460370962
• 负责人: Professor Dr.-Ing. Horst Biermann, since 5/2023
• 金额: --
• 依托单位: Institut für Werkstoffwissenschaft
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/460370962?language=en
• 关键词: Investigations; regarding; novel; combination; treatment

Al alloys are attractive lightweight materials, but their low hardness limits their usability for components under tribological stress. Thin hard coatings, especially diamond-like carbon coatings (DLC), show excellent friction and wear behavior. But due to the lack of supporting effect on soft materials they can only be used to a limited extent. This lack can be eliminated by electron beam (EB) liquid phase surface treatment of the Al substrate and the resulting increase in hardness. The aim of the project is to investigate the material-specific cause-and-effect relationships and the sequence of elastic-plastic deformations and crack formation in the material composite Al-substrate - EB surface layer - DLC coating. This enables a knowledge-based design of the material composite for high loads. For a comprehensive understanding, a scientifically based chain of knowledge of the relationships between process parameters - microstructure - properties - stress behaviour is to be established stepwise. In phase I, a fundamental material and mechanistic understanding of the interface between Al-based model alloy/DLC-coating as a basis for the functionality of a layer composite on soft Al-substrate will be generated. Thereby, the focus is on the analysis of the microstructure of the model alloys and their relevant properties for the desired support and adhesion function for the DLC coating. The stepwise investigation of Al, Al-Si and Al-Si-Ni(x) model alloys allows an easier extraction of the effects of the microstructural constituents on e.g. oxidation and selective sputtering processes, and thus, on the adhesion and load capacity of the DLC coating. The comprehensive analysis of the individual components of the material composite with regard to their mechanical characteristics and the residual stress state is incorporated into the contact modelling. The first step is to generate a realistic elastic load/contact model of the layered composite in order to calculate the complete stress and strain states. Attention is paid to the exceeding of critical von Mises stresses and to crack-critical stress parameters in the interface Al-based model-alloy/DLC-coating as well as within the DLC. The decision whether a stress or strain parameter is ultimately critical, i.e. whether it leads to the initiation or propagation of cracks, is made in comparison with the crack phenomena actually observed in the crack test and in the pop-in analysis by means of nanoindentation. Based on these new basic findings, the transition to application-relevant technical alloys is to be made in phase II in order to be able to interpret the mechanisms of the heterogeneous, multiphase multi-material alloy.

铝合金是一种有吸引力的轻质材料，但其低硬度限制了其在摩擦应力下的部件的可用性。薄的硬质涂层，特别是类金刚石涂层（DLC），表现出优异的摩擦磨损性能。但由于对软材料缺乏支撑作用，只能在有限的范围内使用。这种缺陷可以通过电子束（EB）液相表面处理的Al基板和由此产生的硬度增加来消除。该项目的目的是调查材料特定的因果关系和顺序的弹塑性变形和裂纹形成的材料复合铝基板- EB表面层- DLC涂层。这使得能够针对高负载进行基于知识的材料复合物设计。为了全面理解，逐步建立工艺参数-微观结构-性能-应力行为之间关系的科学知识链。在第一阶段，将产生一个基本的材料和机制的理解之间的界面铝基模型合金/DLC涂层作为一个层复合材料的功能的基础上软铝基板。因此，重点是分析模型合金的微观结构及其相关性能，以获得DLC涂层所需的支撑和粘附功能。Al、Al-Si和Al-Si-Ni（x）模型合金的逐步研究允许更容易地提取微观结构成分对例如氧化和选择性溅射过程的影响，以及因此对DLC涂层的附着力和负载能力的影响。接触建模中纳入了对材料复合材料各个部件的力学特性和残余应力状态的综合分析。第一步是生成层状复合材料的真实弹性载荷/接触模型，以计算完整的应力和应变状态。注意的是超过临界冯米塞斯应力和裂纹临界应力参数的界面铝基模型合金/DLC涂层以及DLC内。应力或应变参数最终是否是关键的决定，即它是否导致裂纹的产生或扩展，是通过与在裂纹测试和通过纳米压痕的弹出分析中实际观察到的裂纹现象进行比较来做出的。根据这些新的基本发现，过渡到应用相关的技术合金将在第二阶段，以便能够解释机制的异质，多相多材料合金。