Fraunhofer ISC, Center for High Temperature Materials and Design HTL, BayreuthCompleted funded project
Motivation
Low-pressure turbine
Fibre-reinforced ceramics (Ceramic Matrix Composites, CMC) have the potential to replace nickel-based alloy components in the low-pressure turbine section of an aircraft engine (e.g. outer air seals, casing structures, stators). Due to the significantly lower density of fibre-reinforced ceramics compared to nickel-based materials, a weight reduction of up to 60% can be achieved by substituting metallic components with CMC materials.
Objective
Work packages HTL
In the project, material characteristics, service life properties and lightweight construction concepts of commercial oxidic and non-oxidic CMC materials were to be determined specifically for the design of engine components. For a future aviation certification of fibre-reinforced ceramics, the basis for a quality assurance concept as well as for a certification strategy was developed.
Results
Pore structure and pore size distribution of a CMC sample (examination by computer tomography)
Damage formation during mechanical loading of different CMC specimens by three-point bending with increasing extreme fibre elongation ε (microstructure images using in-situ computer tomography)
Commercially available ceramic composite materials (CMC) were evaluated in defined fields of properties with a view to subsequent aerospace certification. Both oxide ceramic composites from DLR Cologne and Pritzkow Spezialkeramik as well as silicon carbide fibre-reinforced silicon carbide (SiC/SiC) from MT Aerospace and SGL Carbon were evaluated using destructive and non-destructive testing methods. Similarly, methods for the aerospace-specific testing of CMC as well as concepts for quality testing and quality assurance were developed. Within the scope of the aviation-specific evaluation of commercial CMCs, extensive material characteristics were determined and linked in the form of a database. The determination of characteristic values was concentrated on the following areas:
- Determination of mechanical parameters of CMC materials at room temperature under static and dynamic load (fatigue tests up to 20 million load cycles)
- Determination of thermal and mechanical parameters of CMC materials in the high temperature range up to 1000°
- Investigation of the effects of enginge-specific environmental influences on the material properties
Project Data
| Project Duration | 01.10.2012 - 31.03.2016 |
| Sponsor |
Federal Ministry of Economics and Technology |
| Funding Amount | 500,000 Euro |
| Project Partners | Fraunhofer-Centre HTL MTU Aero Engines AG German Aerospace Centre MT Aerospace AG SGL Carbon SE |
| Project Coordination | MTU Aero Engines AG |
| Project Management at the HTL | Christian Eckardt |
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