Wydarzenia w AGH

Wykład zatytułowany Practical aspects and problems of the repair process of cast Ni-based superalloys used in the aerospace industry wygłosi dr inż. Łukasz Rakoczy z Wydziału Inżynierii Metali i Informatyki Przemysłowej AGH.

Udział

• stacjonarny: ACMiN (ul. Kawiory 30, bud. D-16, II piętro, sala audytoryjna 1.02A)
• zdalny: platforma MS Teams (link)

Streszczenie

Cast Ni-based superalloys have been among the most important materials in the aerospace industry. Numerous scientific papers and information from the industry confirm that Ni-based superalloys can be characterized by an increased susceptibility to hot cracking. However, repair technologies need to be implemented. This mainly applies to the structural reconstruction of castings with minor production defects and the service of the components. It is dictated primarily by economic reasons because of the high price of new components produced via investment casting. Therefore, determining the weldability of a new generation of Ni-
based superalloys, developing a technology to prevent hot cracking, and selecting appropriate filler materials are particularly important and justify research in this area. The key problem of low weldability of superalloys increases with the concentration of elements co-forming with Ni the intermetallic γ' phase, namely Al and Ti. The general criterion for distinguishing between weldable and difficult-to-weld materials is the total concentration of Al and Ti around 6%. Consequently, in many cases, materials with a different chemical composition in comparison to the base material are used in the repair process. The presentation will show a comprehensive research program focusing on the characterization of the pre-weld microstructure, the change of physico-chemical properties with temperature increase and analysis of the hot cracking mechanism of cast Ni-based superalloy. Based on the results, a solution was proposed, which consisted of using induction heating with high-frequency currents to completely eliminate hot cracks during repair welding. It also identified opportunities for developing new repair materials, such as metallic matrix composites (MMC), which could become an alternative to the currently used filler metals.
This work was partially supported by National Centre for Research and Development, Poland, under grant LIDER XIII – Development of the manufacturing and deposition technology of metal-ceramic nanocomposite coatings for the structural reconstruction of heat-resistant nickel-based superalloys (Project no. 0036/L-13/2022).