Solidification of Al Alloys Under Electromagnetic Pulses and Characterization of the 3D Microstructures Using Synchrotron X-ray Tomography

Abstract

A novel programmable electro-magnetic pulse device was developed and used to study the solidification of Al-15%Cu and Al-35%Cu alloys. The pulsed magnetic fluxes and Lorentz forces generated inside the solidifying melts were simulated using finite element methods, and their effects on the solidification microstructures were characterized using electron microscopy and synchrotron X-ray tomography. Using a discharging voltage of 120V, a pulsed magnetic field with the peak Lorentz force of ~1.6 N was generated inside the solidifying Al-Cu melts which was showed sufficiently enough to disrupt the growth of the primary Al dendrites and the Al 2 Cu intermetallic phases. The microstructures exhibit a strong correlation to the characteristics of the applied pulse, forming a periodical pattern that resonate the frequency of the applied electro-magnetic field.

Refinement and growth enhancement of Al2Cu phase during magnetic field assisting directional solidification of hypereutectic Al-Cu alloy

“…TEMF in liquid can generate flow ahead of the solid/liquid interface 19 . This is contrary to the previous knowing that the uniform static magnetic field can only damp the melt flow, and thus drawn a huge of attentions 22 23 24 . Nevertheless, rare work has been done on understanding the influence of TEMF in the solid, and in particular its impact on the formation of primary reinforced phase during solidifying the metal matrix in situ composites.…”

3D Phase Field Modeling of Multi-Dendrites Evolution in Solidification and Validation by Synchrotron X-ray Tomography

“…The alloy was held at ~730 °C for ~1 h to homogenize the melt. The alloy melt was then drawn uphill and poured into a quartz tube of 100 mm long with an inner diameter of 2.5 mm by using a small counter-gravity casting apparatus [ 17 ]. The negative pressure (~0.5 atmospheric pressure) was able to draw the liquid metal into the quartz tubes in a quiescent manner, avoiding any surface turbulence during the filling and minimizing any possible entrainment of air bubbles or oxide films into the cast bar.…”

“…Real-time synchrotron X-ray tomography experiments were carried out at the Tomographic Microscopy and Coherent Radiology Experiments (TOMCAT) beamline of Swiss Light Source, Paul Scherrer Institute, Switzerland using a specially designed pulse electromagnetic field solidification apparatus [ 17 ]. Figure 1 a shows the schematic illustration of the experimental setup.…”

“…In this aspect, a number of numerical methods have been developed recently [ 13 , 14 , 15 , 16 ]. Among them, the adaptive mesh refinement has been proved to be one of the most computationally efficient methods, which has been used in the simulation of a single dendrite growth [ 13 , 14 ], multi-dendrite growth [ 17 ], and interface instability [ 18 ]. However, even with the adaptive mesh refinement, 3D phase field simulation of dendrite coarsening is still a computationally challenging task.…”

Imaging in real and reciprocal space at the Diamond beamline I13

“…More details can be found elsewhere 1,4 . Currently bio-medical and engineering/materials science applications are the most popular, while geo-physical (see figure 3) experiments have also been carried out with great success [8][9][10][11] . Mainly pink beam is used with filtering towards higher photon energies for materials science experiments.…”