A novel gravity-assisted automatic docking device for studying diffusion in liquid metal melts assisted by a strong static magnetic field

Abstract

A novel gravity-assisted automatic docking (GAAD) method is presented for the study of interdiffusion processes in liquid Al–Cu melts. A novel GAAD device was designed to be suitable in a strong static magnetic field (SSMF) with a bore size of 50 mm. Energy dispersive x-ray spectroscopy was used to quantitatively analyze the concentration profiles of diffusion capillaries. The interdiffusion coefficient (DAlCu) was measured by applying Fick’s second law. The combination of SSMF and GAAD made the original diffusion interface be easily determined and not be oxidized. The melt convection was completely reduced to reach the pure diffusion state. The performance of this GAAD measurement method assisted by a SSMF was successfully verified by a diffusion experiment in an Al–Cu melt.

Review on Eutectic-Type Alloys Solidified under Static Magnetic Field

“…The details of the GAAD apparatus can be found in Refs. [55,56]. Results demonstrated that the diffusionlimited condition as measured in microgravity was achieved when the MFD was greater than about 3 T. To further reveal the influence of this diffusive condition on crystal growth, Al-20wt.%Cu hypoeutectic alloy was solidified under a 24 T high SMF (Figure 3d-f) [61].…”

“…Studies have shown that the diffusion coefficient value decreases with the increase in MFD, which provides a simulated diffusive condition [52][53][54]. Recently, a novel gravityassisted automatic docking (GAAD) device was independently developed to measure the interdiffusion coefficient of an Al-Cu alloy (D AlCu ) from 0 T to 22 T and the critical MFD for achieving the diffusion-limited condition [55,56], as shown in Figure 3a-c. The details of the GAAD apparatus can be found in Refs.…”

“…Recently, magnetic dipole-dipole interactions (or magnetic interaction force) have been successfully used to affect grain growth, resulting in elongated grain and chainlike microstructures [40], and control the agglomeration and dispersion of primary crystals [51]. Therefore, the aforementioned forces, which have significant effects on the kinetic processes of solidification, are effective in controlling atom diffusion [52][53][54][55][56], nucleation events [42,57], melt convection [19,34], solute distribution [32,58,59], crystal migration [21,43,60], and morphology evolution [61][62][63] during solidification. Apart from kinetic processes, magnetic energy can also modify thermodynamic events, such as phase transformation and crystal orientation, even in a non-ferromagnetic system [12,64,65].…”

“…Indeed, the crystal orientation is considered to be influenced by the SMF in both thermodynamic and kinetic ways. In the past decade, our group has systematically investigated the role of SMFs in the solidification process, including atomic diffusion [55,56,66,67], dendrite growth [61,68], homogenization of the secondary phase in immiscible alloy [69][70][71], and electroslag remelting in steel [72][73][74]. Based on these studies, we suggested that ETA materials processing under an SMF holds promise for both fundamental scientific research and industrial applications.…”