|Lead by: VN|
|Participating partners: POLIMI, TWI, NAU KHAI, URJC, METALOGIC, AVIO, EADS, EADS-CASA, IMPACT, IBERIA|
Currently several experiments and procedures have been developed concerning MRO in aeronautics, especially on & with Aluminum Alloys. However, the current SoA consist of preliminary and promising results of some isolated tests. CORSAIR challenge is to explode these results testing more alloys and applications; optimizing process characteristics, efficiency and reliability; defining procedures according to aeronautic companies guidelines and finally improving the whole Cold Spray Repair Chain including new and optimized raw materials.
WP5 aims to explore and optimize the deposition process with & on Aluminum and Magnesium Alloys. In order to realize this, the research will deeply characterize the deposited coatings and use these results as feedback for process optimization. Then, the deposition protocols for repaired parts will be defined, including feedstock material selection and post-deposition treatment if necessary. The final results will be compared against commercially available solutions in order to justify their beneficial effect on repair applications.
The WP5 activities are subdivided in 3 Tasks: “Deposition Process Optimization” ; “Characterization of Deposited Coatings” and “Deposition Process Characteristics for application on Aeronautical Components”.
The first task is devoted to prepare specimens with artificial defects taking into account accurately the aeronautical enterprise needs, prepare optimized feedstock powders, and optimize the deposition process both with mechanized and portable units. Post-deposition treatments will be also considered.
The second task is devoted to the realization of an extended Characterization Plan: metallurgical characterization with observation of coating structure and morphology both at micro & nano-scale. Corrosion and stress corrosion performances. Mechanical characterization in terms of hardness and surface properties, tribological behavior, coating adhesion and cohesion (YS, UTS). Residual stress evaluation and fatigue characterization both at room and high temperature. Custom characterization to depict specific performances (wear resistance, surface properties, morphology, etc.) depending on the required application needs.
Experimental results will be also matched with theoretical values predicted by mathematical model developed within WP2 and still used to validate the model. Finally the deposition process will be preliminary evaluated on industrial specimens in view of assessing the expected properties of aeronautical components repaired with CS. This represent the first step to the subsequent demonstration processes planned in WP7.
The outputs of WP5 research will include guidelines for the preparation of the necessary lab specimens, as well as protocols with definitions of the optimized deposition process for each material being studied. These will cover the areas of spray conditions, process preparation and realization.
Additionally, a characterization report will be produced, containing all coating characteristics required to validate the repair applications and correlation with process parameters. Finally, a selection of results and process/materials depositions will be assorted in order to devote to dissemination activities.
June 2013-May 2014 (M01-M12)
The aim of WP5 is the investigation and optimization of cold spray processes on Al and Mg alloy substrates. The activities are carried out in the laboratory, especially on Lab specimens even if the realization of some preliminary deposition on components and prototype can be done.
WP5 has started on M3 with the realization of the deposition process, by using the state-of-art conditions employed in stationary high pressure cold spray system. These are limited in particular to the use of a carrier gas temperature 350°C due to the mandatory use of a polymeric PBI nozzle. The deposition has been carried out with two representative alloys strongly employed in aeronautics: A2024 and AlSi10Mg. The coating has been realized on flat specimens in order to investigate microstructure, microhardness, residual stress and adhesion. Further specimens to deeply investigate the mechanical behavior and corrosion resistance are in preparation.
The second part of WP5 has been devoted (and it is already in progress) to guide CORSAIR beyond the state of art. Firstly, the steady system has been equipped with innovative accessories developed within WP3 in order to test and use them for the Al alloy coating deposition. For instance, specific water cooling of the nozzle has been adapted and installed in the cold spray facility at VN and the gun equipped with a SiC nozzle in order to allow the achievement of gas temperature up to 600°C, avoiding nozzle clogging.
Deposition process investigations with spray conditions beyond state of art are currently in progress. The next steps will be the identification of a new set of optimized deposition parameters and perform a full investigation of coating properties profiting of all knowledge and availability of the consortium and finally the realization of some preliminary prototypes that are planned (and expected) before M18.
The activity of this WP is mainly a research activity so the impact is focused on scientific excellence, however, the process guidelines obtained in Laboratory will represent the tool to start the realization of deposition processes on real components./p>
The activities related to the CORSAIR research are being organized in the following Work Packages (WPs):
- WP1: Roadmap and selection of materials and components
- WP2: Specific process simulation and nozzle design
- WP3: Design and realisation of a new prototype of portable unit for in situ repair
- WP4: Optimisation of powder process manufacturing
- WP5: Coldspray to repair Al and Mg alloy components
- WP6: Coldspray to repair Ti alloy components
- WP7: in-situ and ex-situ repairs of aeronautical components: realization
- WP8: in-situ and ex-situ repairs of aeronautical components: validation
- WP9: Dissemination and exploitation of the results
- WP10: Project management and co-ordination