At IMN; IRDL, Clément Le Falher developed numerical models for MAG-CMT additive manufacturing.
Clément Le Falher, chercheur·e au sein de IMN; IRDL (Institut de Chimie - CNRS Chimie).
Thèse soutenue en 2023 à l'école doctorale École doctorale Matière, Molécules Matériaux et Géosciences (Le Mans).
Référencée dans le réseau ABES/STAR, cette thèse répond aux critères de rigueur de l'enseignement supérieur français.
Additive manufacturing, particularly through the MAG-CMT process (Metal Active Gas - Cold Metal Transfer), represents a significant advancement in the production of metal parts. This innovative technology allows for the creation of large objects while using a minimum of material, addressing growing economic and environmental challenges. Indeed, in a context where sustainability and resource efficiency are becoming paramount, additive manufacturing positions itself as a promising solution. However, mastering plastic deformations and residual stresses remains a major challenge. This is where Clément Le Falher's thesis comes into play, proposing predictive numerical models to better understand these complex phenomena.
Deformations and residual stresses in parts manufactured by material addition are often caused by significant thermal gradients during the deposition of molten metal. These gradients can generate internal stresses that, if not controlled, can compromise the structural integrity of the parts. By developing numerical tools capable of predicting these effects, Le Falher paves the way for improved industrial practices. Two modeling methodologies have been implemented: one neglecting hydrodynamic effects, which can simplify calculations, and the other adopting a multi-scale approach, which takes into account interactions at different levels, from micro to macro. This duality allows for more precise results, essential for optimizing the manufacturing process.
The recommendations of the thesis include the creation of databases on materials, particularly for stainless steel 415, to support the numerical models. These databases would be crucial for engineers and researchers, as they would provide reliable information on the mechanical and thermal properties of materials, thus facilitating their use in real applications. The integration of metallurgical phase transformations into these models is also suggested to improve the accuracy of predictions. Indeed, phase transformations can have a significant impact on the final properties of parts, and their adequate modeling could transform additive manufacturing, ensuring better product quality and reducing waste.
It is crucial to ask how these innovations can be implemented on a large scale. Industrial players must commit to adopting these new technologies to remain competitive in an increasingly demanding market. For example, companies like GE Aviation and Boeing are heavily investing in additive manufacturing to produce lightweight and complex parts, thereby reducing costs and production times. Collaboration between researchers and industry will be decisive in advancing this field. Partnerships between universities, research centers, and companies can promote the transfer of knowledge and expertise, thus enabling faster adoption of innovations.
In summary, this research is not limited to theoretical advancements but proposes concrete solutions for the industry of tomorrow. The implications of this work are vast, not only for the additive manufacturing sector but also for other fields such as aerospace, automotive, and even construction. By integrating these numerical models into the design and manufacturing process, companies can not only improve the quality of their products but also reduce their ecological footprint. Thus, Clément Le Falher's thesis represents not only an academic advancement but a true lever for transforming the industry and addressing contemporary challenges.
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Sources et accès
Clément Le Falher. Modélisation numérique multi-échelle et approche expérimentale du procédé de fabrication additive MAG-CMT pour la prédiction des déformations et des contraintes résiduelles. Matériaux. Nantes Université, 2023. Français. ⟨NNT : 2023NANU4085⟩. ⟨tel-04797783⟩