Process Chain Development for the Fabrication of Three-Dimensional Braided Oxide Ceramic Matrix Composites.

Martin Kolloch,Thomas Gries,Walter Krenkel,Niels Grigat,Georg Puchas,Ben Vollbrecht

doi:10.3390/ma14216338

Martin Kolloch, Thomas Gries + Show 4 more

Open Access

https://doi.org/10.3390/ma14216338

Copy DOI

Abstract

Fiber composites with a three-dimensional braided reinforcement architecture have higher fiber volume content and Z-fiber content compared to a two-dimensional braided reinforcement architecture; as a result, the shear strength increases. Porous oxide fiber composites (OFCs) have the inherent weakness of a low interlaminar shear strength, which can be specifically increased by the use of a three-dimensional fiber reinforcement. In this work, the braiding process chain for processing highly brittle oxide ceramic fibers is modified; as a consequence, a bobbin, which protects the filament, is developed and quantitatively evaluated on a test rig with regard to tension and filament breakage. Subsequently, a braiding process is designed which takes into account fiber-protecting aspects, and a three-dimensional reinforced demonstrator is produced and tested. After impregnation with an Al2O3-ZrO2 slurry, by either a prepreg process or a vacuum-assisted process, as well as subsequent sintering, the three-dimensional braid-reinforced OFC exhibits an interlaminar shear strength (ILSS) which is higher than that of two-dimensional braid- or fabric-reinforced samples by 64–95%. The influence of the manufacturing process on the relative macropore content is investigated and correlated with the mechanical properties.

Highlights

The Climate Protection Plan 2050 for Germany envisages a reduction in greenhouse gases by at least 40% by 2050 compared to the levels in 1990 [1]
Hairiness caused during the winding process increases the damage in the subsequent process steps, since filament breakage increases friction
By modifying the 2D and 3D braiding process chain with the aim of processing the fibers as gently as possible, brittle oxide ceramic fibers could be processed with less damage

Summary

Introduction

The Climate Protection Plan 2050 for Germany envisages a reduction in greenhouse gases by at least 40% by 2050 compared to the levels in 1990 [1]. Oxide fiber composites (OFCs) with a density of 2.4 to 2.9 g/cm have several advantages over the nickel-based superalloys used as the standard material in this temperature range. These include a weight advantage of up to 73% as well as better thermomechanical properties with service lives of over 20,000 h for industrial applications [5,6,7]. Due to their chemical resistance and inherent oxidation stability, even at operating temperatures of over 1000 ◦C in corrosive atmospheres, OFCs are potential key elements for developments in energy conversion and transport technology [6]

Methods

Results

Conclusion