Rapid Solidification of Refractory Metals : An Atomistic Simulation Study
Kaipainen, Joni (2023)
2023
Master's Programme in Science and Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2023-08-03
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202306216874
https://urn.fi/URN:NBN:fi:tuni-202306216874
Tiivistelmä
Rapid solidification occurs in various industrial manufacturing processes, such as additive manufacturing, thermal spray coating and melt spinning. These processes take place in conditions far from equilibrium and can lead to anisotropic kinetic effects that can alter the growth dynamics and contribute to dendritic growth. This can potentially cause the bulk material properties to change drastically when compared to materials that undergo normal, slow solidification. Thus, understanding the underlying physics of solidification is necessary in order to adjust the industrial processes to reach desirable properties.
In this work, the rapid solidification of selected refractory metals Mo, Nb, Ta, V and W, as well as the binary alloys W-Mo, W-Nb, W-Ta and W-V is studied. Due to difficulties in performing experimental work on rapid solidification, atomistic simulations are performed using the open source molecular dynamics software LAMMPS.
Two anisotropic key parameters that describe solidification solidification are calculated from the simulations: the solid-liquid interfacial free energy and the kinetic coefficient. These parameters can then be used in phase-field modelling of these metals. In addition, we investigate the convergence of the layered thermostat method and perform a case study on the rapid solidification of the 5-component Mo-Nb-Ta-V-W Senkov high entropy alloy.
In this work, the rapid solidification of selected refractory metals Mo, Nb, Ta, V and W, as well as the binary alloys W-Mo, W-Nb, W-Ta and W-V is studied. Due to difficulties in performing experimental work on rapid solidification, atomistic simulations are performed using the open source molecular dynamics software LAMMPS.
Two anisotropic key parameters that describe solidification solidification are calculated from the simulations: the solid-liquid interfacial free energy and the kinetic coefficient. These parameters can then be used in phase-field modelling of these metals. In addition, we investigate the convergence of the layered thermostat method and perform a case study on the rapid solidification of the 5-component Mo-Nb-Ta-V-W Senkov high entropy alloy.