Material removal mechanisms in grinding of fiber-reinforced non-oxide ceramics

由于金属高温合金在热阻方面的发展潜力有限，纤维增强陶瓷成为材料发展的重点。分析了陶瓷整体磨削过程中的磨削行为和材料去除机理。几项科学研究表明，脆性材料的延性磨削是可能的。虽然关于纤维增强陶瓷(陶瓷基复合材料)的磨削行为的研究已经发表，但其潜在的材料去除机理在很大程度上是未知的。此外，磨削工艺对表面区的影响也只是零星地进行了研究。为了优化工艺设计，需要进行考虑材料去除机理和深入了解材料的系统测试。该项目的目标是开发一个用于磨削纤维增强非氧化物陶瓷材料去除机理的启发式模型。以C/碳化硅和碳化硅/碳化硅陶瓷为例，定性和定量地描述了纤维取向和纤维材料对加工特性的影响。此外，还将解释磨削参数和由此产生的表面完整性区域之间存在哪些因果关系，以及磨削过程的效果受纤维取向和纤维材料影响的程度。建立了材料去除机理的经验模型，该模型描述了材料性质和磨削工艺参数的函数关系。在此基础上，建立了基于材料特性的启发式模型，该模型解释了磨削后的材料去除机理和表面整体区的性质。

Due to a limited development potential in terms of thermal resistance of metallic superalloys, fiber-reinforced ceramics came into the focus of material developments. The grinding behavior and the material removal mechanisms in grinding of ceramics were analyzed for monolithic ceramics. It has been shown in several scientific works, that ductile grinding of brittle materials is possible. Although investigations regarding the grinding behavior of fiber-reinforced ceramics (ceramic matrix composites (CMCs)) were already published, the underlying material removal mechanisms are largely unknown. Also, the influence of a grinding process on the surface zone is only investigated sporadically. For an optimized process design, systematic tests considering the material removal mechanisms as well as a deep material understanding is necessary.The goal of the project is to develop a heuristic model for the material removal mechanisms in grinding fiber-reinforced non-oxide ceramics. Using the example of C/SiC and SiC/SiC ceramics, the influence of the fiber orientation and the fiber material on the machining characteristics will be described both, qualitatively and quantitatively. Furthermore, it will be explained, which cause-effect relationships between the grinding parameters and the resulting surface integrity zone exist and to what extent the effects of a grinding process can be influenced by the fiber orientation and fiber material. An empirical model will be developed, which describes the material removal mechanisms as a function of the material properties and the grinding process parameters. Based on the findings, a heuristic model will be derived, which explains the material removal mechanisms and the surface integrity zone properties of the workpiece after grinding on basis of the material properties.