In the aerospace industry, weight reduction and energy efficiency are key R&D requirements. Ceramic
fibre composites (CMCs) offer ideal properties here: lower density than nickel-based alloys, up to 300 K
higher high-temperature resistance, natural oxidation resistance and low corrosion tendency. CMC
components in the hot section of gas turbines enable more efficient combustion and increase the
potential of the fuels used. The AirfOx project aimed to expand 3D component production from CMC.
The focus was on the development of a technology for the production of near-net-shape 3D preforms
for aircraft gas turbine engine blades made of oxide ceramic fibres. These were further processed into
energy-efficient high-temperature O-CMC components, supported by multiscale simulation of the
structure-property relationships.
 
In fibre production, mullite and corundum reinforcing fibres were developed. The mullite fibres with
good mechanical properties already produced at the HTL were further improved by additives such as
ZrO2, particularly with regard to their creep behaviour. The feasibility of producing pure corundum fibres
was demonstrated on a laboratory scale and their mechanical properties were optimized. The results
will be transferred to the fibre pilot plant in Bayreuth after the end of the project.
The development of a woven near-net-shape preform for the airfoil went through several phases.
Feasibility was first confirmed and a suitable weave was developed using EAT Weave Composite.
Preliminary tests on a semi-automatic laboratory loom with a simplified weave (canvas in all plies)
allowed important conclusions to be drawn about the weave design. These findings, together with
multiscale simulations for force progression detection, were incorporated into the complex weave
development. The airfoil was finally implemented, optimized and parameterized with oxide ceramic
fibres on a double rapier weaving machine at Fraunhofer Application Centre TFK in Münchberg. In the
process, adjustments were made to the weaving machine, the creel and the machine elements in order
to efficiently process the demanding, brittle fibre material.