The CMC‑TurbAN project, funded by the German federal budget under the code 03XP0189C, ran from 1 December 2018 to 30 November 2021 and was extended to 30 November 2022 because of pandemic‑related delays. Its overarching aim was to investigate and develop ceramic matrix composite (CMC) materials suitable for high‑temperature turbine applications, with a particular focus on silicon‑carbon fibre reinforced silicon carbide (SiCf/SiC) composites. The consortium was led by MTU, with ArianeGroup GmbH as the principal applicant and partner, and included NGS as the supplier of Hi Nicalon Type S SiC fibres. The project was organised into several work packages, the second of which—SiC‑based materials—tasked ArianeGroup with adapting established internal and external manufacturing processes to meet the project’s specific material class requirements.

ArianeGroup designed a novel, fully automated, vertically integrated process chain that satisfied both MTU’s technical specifications and ArianeGroup’s own automation goals. The chain incorporated the use of Hi Nicalon Type S SiC fibres, a boron‑nitride (BN) coating, and a balanced 0°/90° fibre orientation. The process steps, from fibre preparation and BN coating to lay‑up, resin infiltration, pyrolysis, and densification, were documented photographically after each stage (Figure 1). Iterative optimisation over four cycles led to progressive improvements in mechanical performance. In the first iteration, the adapted processes successfully produced SiCf/SiC specimens with the required fibre orientation and BN coating. Subsequent iterations refined the resin system and densification parameters, resulting in a marked increase in tensile and bending strengths. By the fourth iteration, the 4‑point bending tests yielded strengths exceeding 300 MPa, while tensile tests produced values above 250 MPa, thereby meeting the project’s target thresholds. The proportional limit stress surpassed 150 MPa, and the room‑temperature elongation at break exceeded 0.5 %. Porosity measurements remained below 5 %, and the drop in mechanical properties after exposure to 1200 °C stayed under the 30 % limit. These results are summarised in Table 1, which compares the target and achieved values, and illustrated in Figure 9, which plots the evolution of tensile and bending strengths across the four iterations. Computed tomography of the final tensile specimens (Figure 10) confirmed a uniform pore distribution and the absence of large defects, corroborating the mechanical data.

The project’s scientific outcomes demonstrate that the adapted manufacturing route can reliably produce SiCf/SiC composites that satisfy stringent turbine‑grade mechanical criteria while maintaining low porosity and high thermal stability. The iterative approach allowed rapid convergence on a process that balances fibre orientation, BN coating integrity, and densification quality. The collaboration between ArianeGroup, MTU, and NGS facilitated the integration of fibre supply, process design, and performance testing, ensuring that the developed material met both industrial and research benchmarks. Interim reports (HomAS‑TurbAN #01, #02, #03) documented progress and guided further optimisation. The extended funding period allowed the team to address unforeseen challenges and refine the process to achieve the desired mechanical performance, thereby advancing the state of the art for high‑temperature turbine CMCs.