Periodic Reporting for period 2 - NEMARCO (NEW MANUFACTURING ROUTES (FOR NiCrSiFeB ALLOYS) TO REPLACE COBALT IN AIRCRAFT COMPONENTS)
Periodo di rendicontazione: 2022-03-01 al 2023-07-31
The aim of NEMARCO Project, which belongs to the Clean Sky 2 programme, was to “study new nickel self-fluxing alloys and their manufacturing routes for the bleed valves butterfly in replacement of Cobalt alloy”. This project will help to overcome health potential issues regarding wear particles of Cobalt alloys in cabin air, but also the need of higher wear resistant sealing rings, leakage-free valve in new hotter, and more pressurized bleed air systems for the future engines and the future less bleed Environmental Control Systems (ECS).
Two manufacturing routes were studied and developed for obtaining sealing rings prototypes with nickel self-fluxing alloys (NiCrSiFeB alloys): Gravity Casting (GC) and Laser Metal Deposition (LMD) processes
As a result, it was taken knowledge on new production routes for nickel self-fluxing alloys to replace cobalt in sealing rings for aircraft industry. The following aspects were studied: analysis on the limits of the new manufacturing processes, key design-process parameters, high temperature (HT) mechanical behaviour, and environmental impact.
The project pursues the improvement of EU Competitiveness by means of reduction of use of Cobalt (being a critical raw material) in industrial components, empowering centrifugal casting and additive manufacturing companies/suppliers with a new portfolio of NiCrSiFeB alloys for the manufacturing of components oriented to different sectors.
Two manufacturing routes were studied and developed for obtaining sealing rings prototypes with nickel self-fluxing alloys (NiCrSiFeB alloys): Gravity Casting (GC) and Laser Metal Deposition (LMD) processes
As a result, it was taken knowledge on new production routes for nickel self-fluxing alloys to replace cobalt in sealing rings for aircraft industry. The following aspects were studied: analysis on the limits of the new manufacturing processes, key design-process parameters, high temperature (HT) mechanical behaviour, and environmental impact.
The project pursues the improvement of EU Competitiveness by means of reduction of use of Cobalt (being a critical raw material) in industrial components, empowering centrifugal casting and additive manufacturing companies/suppliers with a new portfolio of NiCrSiFeB alloys for the manufacturing of components oriented to different sectors.
During RP2 the main progress was done on the final selection of the 2 most promising composition grades for self-fluxing nickel alloys, and the manufacturing of the tubes preforms by GC and LMD processes for sealing rings prototype machining and grinding. Finally, two sets of sealing rings were tested at Liebherr up to 20,000 cycles and the leakage measured, evaluated and compared against current solutions of sealing rings.
Other major progress was the tribology studies at room and high temperature for the NiCrSiFeB alloys obtained by the two new manufacturing routes proposed in NEMARCO (GC and LMD). High load tests were conducted to generate the debris particles for the toxicity analysis conducted in WP4. The wear kinetics study at variable contact temperature was completed. The main conclusions after tribological characterization and studies conducted in NiCrSiFeB alloys and Stellite 6 reference alloy were stated, determining the wear mechanics, wear response, and the mechanisms of the glaze layer formation in NiCrSiFeB alloys.
During the analysis of wear particles toxicity it was observed that effects were comparable between the wear particles obtained from NiCrSiFeB samples researched in the project and those from the Stellite 6 controls. The LMD process is cheaper than GC manufacturing route for sealing rings prototypes obtained at lab scale. In the best-case scenario the cost of the LMD sealing rings are 30% lower than the sealing rings obtained by GC route. The comparative CO2 emissions between the current industrial manufacturing route (with Stellite 6 and CC process) and the proposed new manufacturing routes (GC and LMD) is biased since in NEMARCO project the measured values and recorded data has been extracted in pilot lab scale processes, not fully representative of a serial industrial production environment. CO2 emissions in the best-case scenario for the LMD manufacturing route of NiCrSiFeB sealing rings are 73% higher than GC manufacturing route.
As an overview of the project results, two alloys (A and C) were selected as the best solutions. The NiCrSiFeB alloys obtained by LMD are more difficult to cut and machine than those obtained by GC, and alloy A shows better machinability than alloy C. The total wear and friction coefficient of Stellite 6 is better than any NiCrSiFeB alloy at room temperature, but alloy C obtained by both GC and LMD processes are better than Stellite 6 evaluated at 300 C, and alloy A obtained by GC and LMD and alloy C obtained by GC are better than Stellite evaluated at 650 C. Alloy C obtained by LMD is the hardest, but it has the worst wear response at both ambient and high temperature as it is unable to form a protective glaze layer, so it wears a lot compared to the other alloys evaluated at high temperature.
The endurance tests of the NiCrSiFeB sealing rings prototypes were performed by mounting two bleed air valves in parallel in the test bench and the leakage was measured after different number of test cycles. Performance curves were obtained as well as a comparison with the current solution (Stellite 6 by CC) and other materials under study by Liebherr as solutions for the sealing rings.
In terms of the exploitation and dissemination results, dissemination activities were reported in each quarterly report, acknowledgement were included in all communications and dissemination of results. All indicators in the PDER were achieved:
• Project website created in M1 and updated in M31
• Press releases and news: 4
• Social media: 12 posts
• Press notes in Partners’ websites
• Scientific and Journalistic articles: 4 (2 published, 1 submitted, 1 writing)
• Participation in workshops & congresses: 7
• Participation in fairs: 1
• Open access datasets: 2
Other major progress was the tribology studies at room and high temperature for the NiCrSiFeB alloys obtained by the two new manufacturing routes proposed in NEMARCO (GC and LMD). High load tests were conducted to generate the debris particles for the toxicity analysis conducted in WP4. The wear kinetics study at variable contact temperature was completed. The main conclusions after tribological characterization and studies conducted in NiCrSiFeB alloys and Stellite 6 reference alloy were stated, determining the wear mechanics, wear response, and the mechanisms of the glaze layer formation in NiCrSiFeB alloys.
During the analysis of wear particles toxicity it was observed that effects were comparable between the wear particles obtained from NiCrSiFeB samples researched in the project and those from the Stellite 6 controls. The LMD process is cheaper than GC manufacturing route for sealing rings prototypes obtained at lab scale. In the best-case scenario the cost of the LMD sealing rings are 30% lower than the sealing rings obtained by GC route. The comparative CO2 emissions between the current industrial manufacturing route (with Stellite 6 and CC process) and the proposed new manufacturing routes (GC and LMD) is biased since in NEMARCO project the measured values and recorded data has been extracted in pilot lab scale processes, not fully representative of a serial industrial production environment. CO2 emissions in the best-case scenario for the LMD manufacturing route of NiCrSiFeB sealing rings are 73% higher than GC manufacturing route.
As an overview of the project results, two alloys (A and C) were selected as the best solutions. The NiCrSiFeB alloys obtained by LMD are more difficult to cut and machine than those obtained by GC, and alloy A shows better machinability than alloy C. The total wear and friction coefficient of Stellite 6 is better than any NiCrSiFeB alloy at room temperature, but alloy C obtained by both GC and LMD processes are better than Stellite 6 evaluated at 300 C, and alloy A obtained by GC and LMD and alloy C obtained by GC are better than Stellite evaluated at 650 C. Alloy C obtained by LMD is the hardest, but it has the worst wear response at both ambient and high temperature as it is unable to form a protective glaze layer, so it wears a lot compared to the other alloys evaluated at high temperature.
The endurance tests of the NiCrSiFeB sealing rings prototypes were performed by mounting two bleed air valves in parallel in the test bench and the leakage was measured after different number of test cycles. Performance curves were obtained as well as a comparison with the current solution (Stellite 6 by CC) and other materials under study by Liebherr as solutions for the sealing rings.
In terms of the exploitation and dissemination results, dissemination activities were reported in each quarterly report, acknowledgement were included in all communications and dissemination of results. All indicators in the PDER were achieved:
• Project website created in M1 and updated in M31
• Press releases and news: 4
• Social media: 12 posts
• Press notes in Partners’ websites
• Scientific and Journalistic articles: 4 (2 published, 1 submitted, 1 writing)
• Participation in workshops & congresses: 7
• Participation in fairs: 1
• Open access datasets: 2
New technical data about HT behaviour of LMD and Casting samples using NiCrSiFeB alloys were obtained. Process parameters set were selected for both new manufacturing routes (GC and LMD) to produce samples for testing and for the manufacturing of tubes preforms for sealing rings prototypes. LCI datasets were created for the aeronautical sector interested in NEMARCO solutions, and the LCIA were made. The LCC Analysis revealed that LMD manufacturing route provides lower costs than the GC manufacturing route. In the best scenario LMD route is 30% lower in cost than the SR obtained by GC route.
A new methodology to characterize the tribological behaviour under high temperatures using a limited number of tests and samples was created by ECL-LTDS.
After endurance tests conducted by Liebherr, the leakage measurements show the good behaviour of the developed materials in NEMARCO. The 3A alloy (LMD route) seems more sensitive to wear especially on external face of the sealing rings. Both exhibits some brittle defects on the sharp edge that should be avoid working on the design and the manufacturing process that still need to be better adapted to these materials. The results are very interesting and the 8A alloy (GC manufacturing route) could represent a robust alternative to Stellite 6 sealing rings.
NEMARCO has contributed to a broader socioeconomic impact, namely: i) Potential reduction of fuel consumption for small-medium range aircraft with the use of new materials and process manufacturing routes, ii) Evaluation of new materials, in this case Nickel based self-fluxing alloys and new more flexible manufacturing routes like metal additive manufacturing, to avoid Cobalt oxidized wear particles in the air flow to the cabin in order to increase the cabin air quality, iii) Reduction of CO2 emissions related to the use of the aircraft due to a reduction of fuel consumption, and related to the manufacturing process because low energy consuming processes like laser metal deposition routes would be used soon, and iv) Reduction of the use of scarce elements and resources like Cobalt.
A new methodology to characterize the tribological behaviour under high temperatures using a limited number of tests and samples was created by ECL-LTDS.
After endurance tests conducted by Liebherr, the leakage measurements show the good behaviour of the developed materials in NEMARCO. The 3A alloy (LMD route) seems more sensitive to wear especially on external face of the sealing rings. Both exhibits some brittle defects on the sharp edge that should be avoid working on the design and the manufacturing process that still need to be better adapted to these materials. The results are very interesting and the 8A alloy (GC manufacturing route) could represent a robust alternative to Stellite 6 sealing rings.
NEMARCO has contributed to a broader socioeconomic impact, namely: i) Potential reduction of fuel consumption for small-medium range aircraft with the use of new materials and process manufacturing routes, ii) Evaluation of new materials, in this case Nickel based self-fluxing alloys and new more flexible manufacturing routes like metal additive manufacturing, to avoid Cobalt oxidized wear particles in the air flow to the cabin in order to increase the cabin air quality, iii) Reduction of CO2 emissions related to the use of the aircraft due to a reduction of fuel consumption, and related to the manufacturing process because low energy consuming processes like laser metal deposition routes would be used soon, and iv) Reduction of the use of scarce elements and resources like Cobalt.