Hybridization of metal 3D printing processes for more resistant parts

Research Defense and Security

Bringing together three prestigious engineering schools under the supervision of the French Defense Procurement Agency (DGA), École Polytechnique, ENSTA, and ISAE Supaero, the QUADS2 project aims to hybridize two metal additive manufacturing processes. The challenge of this new process is to successfully manufacture complex-shaped stainless steel parts while limiting their environmental impact, as well as to repair existing parts.

The QUADS1 project, carried out between 2020 and 2024 with the same partners, has enabled the qualification of two additive manufacturing processes for stainless steel: Laser Powder Bed Fusion (L-PBF) and Laser Powder-Direct Energy Deposition (LP-DED).

During the first project, the parameters of both processes were optimized. Tests validated the fatigue and corrosion resistance of the parts created. Their mechanical and electrochemical properties are equivalent to or even superior to those of alloys produced using traditional processes such as forging, casting, or machining.

Matthieu Dhondt Researcher at ENSTA/IRDL

The challenge for QUADS2 (2025-2028) is to go further by hybridizing these two additive processes in order to test the opportunities offered by this new process in terms of part manufacturing or repair. It also involves analyzing the impact of hybridization/repair on the fatigue and corrosion resistance of these parts.

" Each process is suited to a specific type of part. To put it simply, one process is used to create large parts, while the other is used to manufacture smaller, thinner parts with complex shapes. Combining the two processes is part of a drive to make structures lighter, but it requires overcoming scientific and technical obstacles".

Examples of hybridization of the two additive processes LPBF and LP-DED [1]

The project will enable hybrid samples to be produced and tested with different loading effects (tension, shear) in order to study the location of deformation and damage at the microstructure level, as well as the mechanisms of crack initiation and propagation. Corrosion resistance is also one of the parameters being studied.

Funded by the Interdisciplinary Center for Defense and Security (CIEDS) with the support of the Defense Innovation Agency, QUADS2 brings together faculty, engineers, and technicians from the three partner institutions, as well as dedicated staff: three doctoral students, one postdoctoral researcher, and one research engineer spread across the three campuses (Palaiseau, Brest, and Toulouse).

The final stage of the project consists of creating a physical demonstrator in order to test a structural test piece in terms of fatigue and/or corrosion resistance under conditions close to real-life stresses and to test the repair protocols developed as part of the project.

Key information
  • Project name: QUADS2
  • Duration: 48 months
  • Partners: LMS Laboratory/Ecole Polytechnique, ICA/ISAE-SUPAERO Laboratory, IRDL Laboratory/ENSTA, IMSIA Laboratory/ENSTA
  • Funding: CIEDS/AID

[1] B. Graf, M. Schuch, R. Kersting, A. Gumenyuk, M. Rethmeier, Additive Process Chain using Selective Laser Melting and Laser Metal Deposition, Lasers in Manufacturing Conference 2015, p.59.

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