Entwicklung neuartiger faserkeramischer C/C-SiC Verbundwerkstoffe auf Basis der Wickeltechnik für Raketendüsen

Kurzfassung

Filament winding technique in combination with the liquid silicon infiltration process (LSI) is used for the development of novel, damage tolerant, high temperature resistant, dense C/C-SiC ceramic matrix composite materials for rocket nozzle extension applications. With the integration of the filament winding technique into the well-known LSIprocess, axisymmetric C/C-SiC structures can be manufactured. The systematic development approach is to manufacture panels, cylindrical samples and eventually a nozzle structure. The influence of different carbon fibers on the resulting mechanical, microstructural and thermophysical properties of novel C/C-SiC materials is evaluated. Additionally, the panels are manufactured with different defined winding angles (angle-ply laminate) to study the influence of the fiber orientation on the final material properties. The extensive material characterization on panel level allows correlations between fiber type, the fiber orientation and the resulting CMC material properties. Consequently, a suitable fiber-matrix configuration for the manufacture of axisymmetric C/C-SiC structure is identified. In order to analytically determine the fiber-dependent mechanical behavior of wound C/C-SiC, e. g. stiffness behavior, for any given symmetric angle-ply laminate, the inverse-laminatetheory is applied. The calculated values are compared with the experimental results. The stress-dependent material behavior of carbon fiber reinforced ceramic matrix composites C/C-SiC material is investigated with modal acoustic emission (AE) technique. For a better understanding and identification of different damage mechanisms C/C-SiC composites with different fiber orientations are studied. The influence of the fiber architecture on the resulting quality of the laminate structure of axisymmetric wound C/C-SiC structures, e. g. delaminations due to process induced matrix shrinkage, is examined. A generic approach for an optimized fiber architecture design for axisymmetric LSI-based C/C-SiC materials is presented, which will reduce the affinity of flaws. The feasibility of an adapted multi-angle fiber architecture and consequent improvement of the laminate quality is demonstrated and assessed using cylindrical specimens. Furthermore, the LSI-process route is adapted with an additional process step (carbon re-infiltration) leading to an reduction of residual silicon and consequently improving the 13 Abstract microstructural composition of the resulting axisymmetric wound C/C-SiC structures. With regard to an efficient manufacturing process the production time is significantly reduced compared to the classical LSI-process providing the same material quality. Finally, for the first time a partially double-walled, integral C/C-SiC nozzle structure is manufactured using an adapted fiber architecture to minimize delaminations, in combination with an adjusted, short and efficient novel LSI-process. The produced nozzle structure is intensively characterized and assessed with internal helium pressure tests. The quality of the net-shape manufacture is demonstrated by means of CT-analysis. The inverse-laminate-theory calculations of C/C-SiC material at panel level provide the exact stiffness properties to a complex fiber architecture used for the nozzle strucutre. The complex fiber architecture and the corresponding stiffness properties are implemented into a finite element analysis, which is then conducted to compare the deformation of the C/C-SiC nozlle structure during the internal helium pressure test. With the successful demonstration of the manufacture of novel C/C-SiC nozzle structures new CMC rocket nozzle applications could be served, which will use the combination of filament winding technique and an adapted liquid silicon infiltration process.