Mobile ElectroMagnetic Levitation (EML) facility
This Mobile ElectroMagnetic Levitator has a flat-panel detector, high-frequency generator, induction coil, pyrometer and video camera laser and has been used to study the solidification of HEA and ternary alloys.
The sample environment
The levitation sample environment is described in the Technical Report: O. Shuleshova (2017) IFW Dresden Annual Report 2017.
www.ifw-dresden.de/uploads/users/10/uploads/files/JB_2017.pdf
Studies of alloy solidification
In their work, Andreoli et al. studied the solidification of CoCrFeNi HEA as well as CrFeNi and CoCrNi ternary alloys, also NbTiVZr HEA has been investigated. The EML facility was used to levitate the samples and heat them by induction heating using a water-cooled copper coil with an inner diameter of 1 mm, up to a temperature higher than 2000 K (higher than the melting temperature).
The samples were placed in the P21.1 scattering chamber, under a high purity He atmosphere at pressure of 500-700 mbar. The scattering chamber of P21.1 allows work under vacuum or in a He atmosphere, it has an angular opening of 30° and various sample environments such as heating devices can be placed inside (see P21.1 website in section 4 for more information)
The cooling was performed utilizing a He jet with a flux of 25 l/min. In-situ XRD measurements were performed in order to follow the crystallization of the samples with respect to the temperature during solidification and depending on the alloy composition.
Experiments were performed at the Swedish Materials Science beamline's P21.1 branch and published:
- A.F. Andreoli, O. Shuleshova, V.T. Witusiewicz, Y. Wu, Y. Yang, O. Ivashko, A.-C. Dippel, M. v. Zimmermann, K. Nielsch, I. Kaban, In situ study of non-equilibrium solidification of CoCrFeNi high-entropy alloy and CrFeNi and CoCrNi ternary suballoys, Acta Materialia. 212 (2021) //doi.org/10.1016/j.actamat.2021.116880
- A.F. Andreoli, R.G. Mendes, V.T. Witusiewicz, O. Shuleshova, M.A. van Huis, K. Nielsch, I. Kaban, Phase constitution and microstructure of the NbTiVZr refractory high-entropy alloy solidified upon different processing, Acta Materialia. 221 (2021) doi.org/10.1016/j.actamat.2021.117416