Nicolas Nothomb
PhD student
Ir. at UCLouvain in 2020

Main project: Improving the fatigue life of high strength aluminum parts (7xxx) produced by laser powder bed fusion
Funding: ERC
Supervisor(s): Aude Simar

Laser Powder Bed Fusion (L-PBF) is a fast-growing metal Additive Manufacturing (AM) technique (commonly known as 3D printing) that allows for complex part manufacturing and small production series. One of the main drawbacks is the limited material palette currently available and the often poor fatigue performance of the resulting parts. Currently, L-PBF does not allow the production of high performances aluminium alloys parts adapted for the aerospace industry. Indeed, these alloys exhibit severe cracking due to the high thermal gradients during L-PBF process.

The overarching objective of my PhD thesis project is to overcome the challenges of the L-PBF processing of the 7xxx series Al alloys in order to improve their fatigue life. This objective involves the elimination of the three classical issues associated with this process ; (i) the elimination of the deleterious hot cracking, (ii) closing of the porosity and (iii) overcoming the poor surface quality classically observed for AM components. The proposed approach has two major advantages. First, the application of friction stir processing (FSP) to selected regions of structural components ensures defect-free microstructures at locations of stress concentration. This is essential to enhance the quality and reliability needed for generalizing the adoption of metal AM for structural components. Indeed, even very small fractions of porosity will affect fatigue properties. Second, the surface roughness is improved in situ, i.e. AM components can be used in as-printed condition, as opposed to classical surface post-treatments currently preventing the design of AM components with complex internal geometries (where surface finishing by conventional post-treatments is impossible).

Mechanisms leading to failure under static or cyclic loading will be analysed using in-situ techniques (microtomography and crack propagation with image correlation).

IMMC main research direction(s):
Processing and characterisation of materials

additive manufacturing
electron microscopy
fracture mechanics
metallic alloys
microstructure-processing relationships
selective laser melting (slm)

Research group(s): IMAP

Recent publications

See complete list of publications

Conference Papers

1. Simar, Aude; Hannard, Florent; Lezaack, Matthieu; Han, Sutao; Santos Macias, Juan Guillermo; Zhao, Lv; Gomes Affonseca Netto, Nelson; Arseenko, Mariia; Gheysen, Julie; Nothomb, Nicolas; Idrissi, Hosni; Ding, Lipeng; Kashiwar, Ankush; Pyka, Grzegorz. Friction stir: much more than welding!. 2021 xxx.