1. Ultrafine Fe-Fe2Ti eutectics by directed energy deposition: Insights into microstructure formation based on experimental techniques and phase field modelling
- Author
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Andreas Weisheit, S. Milenkovic, J. C. da Silva, Katrin Bugelnig, Ulrike Hecht, Jan Haubrich, Guillermo Requena, László Gránásy, G. Rödler, Tamás Pusztai, Federico Sket, A. Theofilatos, Pere Barriobero-Vila, Joachim Gussone, DLR Institut für Werkstoff-Forschung / Institute of Materials Research, Deutsches Zentrum für Luft- und Raumfahrt [Köln] (DLR), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, European Synchrotron Radiation Facility (ESRF), ACCESS (GERMANY), Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, and Publica
- Subjects
0209 industrial biotechnology ,Materials science ,Additive manufacturing ,Fabricació additiva ,Alloy ,Biomedical Engineering ,Nucleation ,02 engineering and technology ,engineering.material ,Enginyeria dels materials [Àrees temàtiques de la UPC] ,Industrial and Manufacturing Engineering ,[SPI.MAT]Engineering Sciences [physics]/Materials ,020901 industrial engineering & automation ,[CHIM.ANAL]Chemical Sciences/Analytical chemistry ,Phase (matter) ,Deposition (phase transition) ,General Materials Science ,Lamellar structure ,Composite material ,Directed energy deposition ,Engineering (miscellaneous) ,Computed tomography ,Eutectic system ,Phase-field simulations ,Ultrafine eutectics ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Microstructure ,Casting ,engineering ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,0210 nano-technology - Abstract
International audience; We investigated the Fe-Fe 2 Ti eutectic microstructure obtained by Direct Energy Deposition (DED) with a hypereutectic composition of Fe-17.6 at.% Ti. Ultrafine lamellar spacings as low as 200 nm were achieved, features which otherwise can only be obtained in thin specimens, e.g. by suction casting. However, at interlayer boundaries (ILBs) a globular morphology of the primary Fe 2 Ti phase is observed with halos of the Fe phase. For the given DED conditions the crystalline structure is thus discontinuous across the ILBs. Both 2D and 3D analysis methods were used to quantify the microstructure, including high resolution synchrotron holographic X-ray computed tomography (HXCT). The generic behaviour of eutectic systems under conditions that qualitatively correspond to those of laser additive manufacturing was explored by phase-field modelling for selected nucleation scenarios and alloy compositions spanning from eutectic to hyper-eutectic. While providing valuable insights into microstructure formation, the simulations point out the need to further deepen our understanding about melting under additive manufacturing conditions in order to implement suitable nucleation and / or free growth models. The simulations also show that globular ILBs can be prevented when using exactly eutectic alloy compositions.
- Published
- 2020
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