Effect of Magnetic-Mechanical Coupled Stirring on the Distribution of B₄C Particles in Al-B₄C Composites

The Al-B₄C composites are interestingly used for neutron shielding due to its low weight, high strength, and neutron absorbing. However, during manufacturing process of Al-B₄C composites, high content of B₄C which leads to aggregation is main problem, as well as the low content resulting in poor neutron absorbing. To solve these problems, this study tries to improve the stirring systems by applying a magnetic field based on traditional mechanical stirring and changing the number and shape of the blade of impeller to enhance the flow of the turbulent kinetic energy to maximizes molten aluminum stirring effects. Compared to the traditional mechanical stirring, simulation, and experimentation showed magnetic-mechanical coupled stirring has the higher turbulent kinetic energy, and the dead region is greatly reduced. From the numerical investigations and experiments in the present work, an optimal configuration was selected based on the particle distribution in the magnetic-mechanical coupled stirring. When the stirring time is 30-40 min, the Al-31 wt.% B₄C composites were successfully manufactured and with the B₄C particles homogeneously distributed in matrix.