Periodic Reporting for period 1 - ROSAMA2 (RObust and Sustainable Additive Manufacturing of Amorphous Metallic Alloys)
Période du rapport: 2022-11-01 au 2025-06-30
Bulk metallic glasses are metals with unique amorphous structures granting them exceptional properties (such as high strength). However, their use is limited because traditional casting methods can only produce relatively small and simple geometries.
Additive manufacturing (AM), and in particular laser powder bed fusion (LPBF), offers a promising alternative, potentially allowing a broader use of BMGs in advanced applications. LPBF can achieve high cooling rates needed to maintain the amorphous structure, potentially allowing larger or more complex BMG parts to be produced. However, several challenges remain. As an example, BMGs made via LPBF often show lower ductility than cast ones, largely attributed to internal defects and/or oxygen contamination.
To address such challenges, the project sets out the following objectives:
- Understand and improve the printability of BMGs using a unique LPBF system that allows in situ 3D imaging of defect formation at synchrotron facilities (herein employed at ESRF on beamline BM18).
- Understand how defects impact material properties in order to improve their performances.
- Studying how BMG powder degrades with reuse and developing strategies to improve recyclability, and therefore sustainability.
This project addresses critical challenges of AM of BMGs. It targets the three above-mentionned interconnected objectives, and thus it directly responds to Europe’s strategic priorities.
Work Package 1 lays the foundation for the project by exploring how process parameters affect defect formation during LPBF. A miniature, custom-built LPBF replicator is specifically designed for use with synchrotron X-ray tomography. It allows researchers to observe defect population formation in situ and in 3D inside the produced parts. This capability is supported by a Long Term Project allocation at ESRF, ensuring dedicated access to beamtime. These insights help define optimal printing conditions.
Work Package 2 addresses the need for robust mechanical performance in BMGs by LPBF. Using state-of-the-art tools, including nano-indentation, compression testing, high-resolution microscopy, and synchrotron X-ray tomography, the materials are characterized at the micro and nanoscale, comparing AM samples to their cast equivalents.
Work Package 3 tackles an additional challenge for AM sustainability, which is material reuse. By analyzing the degradation mechanisms of BMG powders during repeated LPBF cycles, the project aims to develop strategies to limit material waste.
The project’s expected impacts are significant in scientific and also in industrial terms. Industrially, it has the potential to unlock new applications for BMGs in sectors such as aerospace, medical devices, and tooling. In addition, by advancing the recyclability and efficiency of AM materials, it contributes to a more sustainable and resilient European manufacturing ecosystem.
Additive manufacturing (AM), and in particular laser powder bed fusion (LPBF), offers a promising alternative, potentially allowing a broader use of BMGs in advanced applications. LPBF can achieve high cooling rates needed to maintain the amorphous structure, potentially allowing larger or more complex BMG parts to be produced. However, several challenges remain. As an example, BMGs made via LPBF often show lower ductility than cast ones, largely attributed to internal defects and/or oxygen contamination.
To address such challenges, the project sets out the following objectives:
- Understand and improve the printability of BMGs using a unique LPBF system that allows in situ 3D imaging of defect formation at synchrotron facilities (herein employed at ESRF on beamline BM18).
- Understand how defects impact material properties in order to improve their performances.
- Studying how BMG powder degrades with reuse and developing strategies to improve recyclability, and therefore sustainability.
This project addresses critical challenges of AM of BMGs. It targets the three above-mentionned interconnected objectives, and thus it directly responds to Europe’s strategic priorities.
Work Package 1 lays the foundation for the project by exploring how process parameters affect defect formation during LPBF. A miniature, custom-built LPBF replicator is specifically designed for use with synchrotron X-ray tomography. It allows researchers to observe defect population formation in situ and in 3D inside the produced parts. This capability is supported by a Long Term Project allocation at ESRF, ensuring dedicated access to beamtime. These insights help define optimal printing conditions.
Work Package 2 addresses the need for robust mechanical performance in BMGs by LPBF. Using state-of-the-art tools, including nano-indentation, compression testing, high-resolution microscopy, and synchrotron X-ray tomography, the materials are characterized at the micro and nanoscale, comparing AM samples to their cast equivalents.
Work Package 3 tackles an additional challenge for AM sustainability, which is material reuse. By analyzing the degradation mechanisms of BMG powders during repeated LPBF cycles, the project aims to develop strategies to limit material waste.
The project’s expected impacts are significant in scientific and also in industrial terms. Industrially, it has the potential to unlock new applications for BMGs in sectors such as aerospace, medical devices, and tooling. In addition, by advancing the recyclability and efficiency of AM materials, it contributes to a more sustainable and resilient European manufacturing ecosystem.
The team conducted comprehensive characterization of spatter particles generated during LPBF processing using advanced microscopy techniques including scanning and transmission electron microscopy with automated crystallographic orientation mapping, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. This analysis revealed that vapor-entrained particles undergo partial melting, leading to the formation of micron-sized crystals and nanocrystals in heat-affected zones. The research established critical connections between spatter characteristics, glass properties, and lack-of-fusion defects, providing fundamental insights into feedstock degradation mechanisms. An additional accomplishment was the implementation of synchrotron X-ray computed tomography during LPBF processing, enabling in situ imaging of pore formation and evolution during part production. This cutting-edge, non-destructive technique provided unprecedented insights into consolidation mechanisms, particularly the effects of laser rescanning on layer surface roughness and powder recoating homogeneity. The research demonstrated that laser rescanning effectively densifies metallic glasses while preserving their amorphous nature. And it revealed the critical importance of the hatch spacing effect in processing viscous metallic glasses. Finally, a significant result was to demonstrate that controlled pore distribution can enhance the mechanical properties of LPBF-produced metallic glasses.
Overall, the work provides foundational insights and practical strategies for improving the quality, structural integrity, and mechanical performance of metallic glass components produced by LPBF.