Additive manufacturing of single crystalline Ni-based superalloy structures

October 7, 2021

Airplane engine turbine blades are subject to extreme operating environments. This fact reduces the life of these parts. Economically, repair is significantly more cost-effective when compared to manufacturing new parts. These are currently produced in monocrystalline nickel superalloys. This means that the repair process cannot be conventional, as they do not preserve monocrystallinity. Laser-assisted metal epitaxial deposition is an additive manufacturing technique that allows metal deposition ensuring monocrystallinity. In this technique, solidification occurs by columnar dendritic growth, where epitaxy is obtained between the substrate and the deposited material. This technique has already been applied on substrates with deposition surfaces with crystallographic orientation {100}, as dendrites, having a highly crystallographic growth (<100> for nickel superalloys) have a higher growth rate, suppressing other misaligned dendrites, with orientations many different. To repair existing defects such as cracks, the surface orientation may not match the {100} orientation. It is necessary to study the behavior under unfavorable crystallographic conditions for the directional growth of dendrites. Laser-assisted metal deposition of the René N4 alloy on a substrate with orientation {101} was performed. In this case study, epitaxy was achieved, and the substrate orientation was preserved for a certain number of layers, after which there was suppression of growth by other dendrites with more favorable orientation. New understanding was reached about this technique, but several studies and parameter optimization are still needed to be able to use it as a repair technique.

Authors in the community:

• 

  F

  Filipe Lopes Silvestre

  ist424702

Supervisors of this institution:

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  M

  Maria Amélia Martins de Almeida

  ist13287

mechanical-engineering - Mechanical engineering

por - Portuguese

Instituto Superior Técnico