ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Multiscale modelling of laser sintering and solidification of ultrafine composite powders of Fe-Ni alloys

Date: 12.09.2011
Place: EUROMAT 2011 - European Congress on Advanced Materials and Processes, Montpellier, France

Ekaterina Abramova
Mikhail Krivilyov, Department of Physics, Udmurt State University, Izhevsk, Russian Federation
Evgeny Kharanzhevskiy, Udmurt State University, Izhevsk, Russian Federation
Denis Danilov, Udmurt State University, Izhevsk, Russian Federation
Vladimir Lebedev, Udmurt State University, Izhevsk, Russian Federation
Peter Galenko, Faculty of Physics and Astronomy, Deutsches Zentrum für Luft- und Raumfahrt, Köln, Germany

Laser sintering of powder materials is a new promising technique suitable for production of a wide range of wear-resistant and corrosion-proof materials. In the present work we present results on multiscale modeling of laser sintering at the macro- and meso-lengths and time scales. Meso-scopic modeling of solute segregation during re-solidification of powder particles was performed using the phase field method while macroscopic simulation of transient heat transfer was done by a model of two-phase mushy zone. According to the results of modeling, the final microstructure of powder particles strongly depends on the processing conditions. Under continuously operating laser significant powder compaction occurs coupled with enhanced solute redistribution driven by convection in the melted zone. Impulse laser treatment allows achieving partial melting of the powder leaving the porous structure of the layer. Phase field modeling showed the effect of solute trapping in high-speed scanning laser sintering. This happens due to high solidification velocities up to 1-5 m/s in the skin shells of the particles. Combined with the large temperature gradient (with values up to 106 K/m), absolute stability of the solidification front is realized leading to chemically homogeneous composition upon re-soldification of powder particles. Comparison with data of XPES analysis of sintered layers is discussed.

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