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

由于金属高温合金在耐热性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，脆性材料的韧性磨削是可能的。虽然关于纤维增强陶瓷（陶瓷基复合材料（CMC））的磨削行为的研究已经发表，基本的材料去除机制在很大程度上是未知的。此外，磨削过程对表面区域的影响只是偶尔调查。为了优化工艺设计，必须进行考虑材料去除机理的系统试验以及对材料的深入理解。本项目的目标是开发纤维增强非氧化物陶瓷磨削材料去除机理的启发式模型。以C/SiC和SiC/SiC陶瓷为例，定性和定量地描述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所得到的表面完整性区域之间存在何种因果关系，以及磨削过程的效果在多大程度上受纤维取向和纤维材料的影响。将开发一个经验模型，该模型描述了材料去除机制作为材料特性和磨削工艺参数的函数。基于这些发现，将推导出一个启发式模型，该模型根据材料特性解释了磨削后工件的材料去除机制和表面完整区特性。

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.