Investigation of thermoelectromagnetic effect at metal wire arc additive manufacturing

I. Kaldre - V. Felcis

I. Kaldre, V. Felcis University of Latvia, 3 Jelgavas str., Riga LV-1004, Latvia

Abstract
Metal additive manufacturing (AM) is a rapidly developing new technology. During the AM process, a small quantity of metal is melted and then solidified. During the melting phase, a small melt pool is formed, where different physical phenomena take place which affect the heat and mass transfer in the melt pool and, hence, the solidified material morphology and microstructure. Solid and liquid phases have different Seebeck coefficients, thus, when subjected to a high thermal gradient, thermoelectric currents may appear at the solid-liquid interface. If exposed to the magnetic field, the Lorentz force drives the liquid phase convection. This small-scale melt circulation allows controlling heat and mass transfer. Different direction and strength of the magnetic field allow achieving a different convection type. In this work, we present an experimental scale model to quantify the role of thermoelectromagnetic effect in a melt pool during the wire arc additive manufacturing process. The experimental setup is a copper hemispherical cavity filled with liquid GaInSn with an immersed cobalt electrode. Heat flux is applied through the cobalt electrode, and thermoelectric currents are generated at the interface between the electrode and the liquid metal. The liquid metal motion created by different orientation of the static magnetic field up to 0.1 T is measured. This result is compared with the numerical model and analytical estimations. Experimental and numerical results demonstrate that the thermoelectromagnetic effect can be significant during the additive manufacturing process. Tables 1, Figs 4, Refs 10.