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Non-monotonic changes in critical solidification rates for stability of liquid-solid interfaces with static magnetic
1State Key Laboratory of Advanced Special Steel, College of Materials Science and Engineering, Shanghai University, Shanghai 200072, PR China.
Scientific Reports
|February 6, 2016
Summary
The study reveals how magnetic fields affect the critical solidification rate, influencing liquid-solid interface stability. This research details the complex interplay between magnetic fields, convection, and solute build-up in materials processing.
Area of Science:
- Materials Science
- Physics
- Fluid Dynamics
Background:
- Understanding the stability of liquid-solid interfaces is crucial for controlling material properties during solidification.
- External fields, such as magnetic fields, can significantly influence melt convection and interface dynamics.
- Thermoelectromagnetic convection (TEMC) and magnetohydrodynamic (MHD) effects are key phenomena in magnetic field-solidification interactions.
Purpose of the Study:
- To investigate the magnetic field dependence of the critical solidification rate for liquid-solid interface stability.
- To elucidate the mechanisms by which magnetic fields alter convection and solute distribution at the interface.
- To correlate experimental observations with numerical simulations of magnetic field effects.
Main Methods:
- Experimental measurements of critical solidification rates under varying magnetic fields and temperature gradients.
- Numerical simulations to model convection velocity and contour at the liquid-solid interface.
- Analysis of solute build-up and liquid-side concentration variations with magnetic field intensity.
Main Results:
- The critical solidification rate exhibits a complex dependence on magnetic field intensity: increasing, then decreasing, then increasing again.
- Magnetic field effects on solidification rate are more pronounced at lower temperature gradients.
- Numerical simulations confirm that TEMC and MHD damping influence interface stability through convection and solute build-up.
- Convection velocity and interface contour show non-monotonic changes with increasing magnetic field intensity.
Conclusions:
- Thermoelectromagnetic convection (TEMC) initially enhances interface stability by micro-stirring the melt.
- Magnetohydrodynamic (MHD) damping leads to solute build-up, causing a decrease and subsequent increase in interface stability.
- The observed variations in liquid-side concentration support the proposed mechanism of magnetic field influence on interface stability.
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