Simulation of electron beam motion behaviors under stable magnetic fields
The electron beam,characterized by high energy concentration and high energy conversion efficiency,is widely applied in many metal processing fields,such as metal refining and additive manufacturing.When external magnetic field was introduced into electron beam melting process,the metallurgical process,solidification structure can be regulated,thus improving the performance of metals.But the electron beam will be deflected by magnetic field from the original straight route,resulting in the positional shift of the molten area.Regarding to this issue,the motional behaviors of single electron and electron beam under stable magnetic field with different magnetic intensities,the emitting angles,the scanning angles and emitting distances were modeled and analyzed based on the simulation software COMSOL.The results indicate that the behaviors of electron beams are similar to the electrons,the required critical emitting angle and scanning angle must be met to realize the electron beam melting under one certain external stable magnetic field.For instance,the emitting angle should be lower than 35° under 0.15 T of magnetic field,and the scanning angle must range between-3.5° to+3.5° in the case of 0 of the emitting angle.Higher magnetic field leads to stronger deflection of electrons(or beams),and meanwhile the critical conditions would be tighter.The magnetic field have effects of filtering,focusing and constraining on electrons(or beams),and the electrons(or beams)are able to enter the crucible independent from the emitting distance once the critical emitting and scanning angle conditions are met.This study can provide a guidance to the development of magnetic field assisted electron beam melting technology and other related technologies.
electron beam meltingmagnetic fieldcharged particle motionnumerical simulation
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