Book/Dissertation / PhD Thesis

FZJ-2021-05551

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Synthese von Cr$_{2}$AlC MAX-Phasen Kompositen und Bestimmung ihrer oxidativen Eigenschaften

Go, T. (Corresponding author)FZJ*

2021
Forschungszentrum Jülich GmbH Zentralbibliothek Verlag Jülich
ISBN: 978-3-95806-598-7

Please use a persistent id in citations: http://hdl.handle.net/2128/29857

Abstract: Three different ceramic matrix composites (CMCs) were produced using Cr$_{2}$AlC as a matrix, and carbon, SiC, and Al$_{2}$O$_{3}$ short fibers as a secondary phase. Cr$_{2}$AlC powders were synthesized by solid-state reaction, followed by mixing with the fibers, and full densification using a field-assisted sintering technique (FAST/SPS). Carbon fibers react strongly with Cr$_{2}$AlC, meaning that these composites are not suitable for use, while the reaction of SiC fibers is less strong. The composites containing alumina fibers do not exhibit any reaction. Oxidation tests of the monolithic Cr$_{2}$AlC and the composites were performed by thermogravimetric analysis. Of all the chosen CMCs, 10 wt.% SiC fibers resulted in the lowest mass gain. The parabolic and cubic rates of oxidation were determined to find the best fitting calculation. The overall oxidation response is parabolic. The alumina layer formed at 1000 °C is well attached and the oxidation response is good. However, at 1200 °C, this layer detached for monolithic material and 10 wt.% Al$_{2}$O$_{3}$ fibers. In long-term oxidation tests at 1200 °C for 4 weeks, a strong reaction of the CMCs in contrast to the monolithic material is observed. The oxidation response of the alumina fiber CMC is good under realistic conditions using a burner rig for cyclic oxidation, as defects or degradation are barely visible, and the alumina layer is well attached. The mechanical reinforcement effect of the fibers was implemented by measuring the compressive streng that room temperature and 900 °C. This reinforcement is clearly evident here. CMCs with Al$_{2}$O$_{3}$-fibers with stand higher compressive stresses than monolithic material. The highest compressive stresses are measured in CMCs with SiC fibers, whereby the reason for this increase can also lie in the secondary phases that arise during sintering.

Note: RWTH Aachen, Diss., 2021

---

Contributing Institute(s):

1. Werkstoffsynthese und Herstellungsverfahren (IEK-1)

Research Program(s):

1. 899 - ohne Topic (POF4-899) (POF4-899)

Appears in the scientific report 2021

---

Database coverage:
;

---