行波磁场对ZL205A合金凝固组织及性能的影响

The effects of different magnetic field excitation currents on the solidification microstructure and mechanical properties of ZL205A alloy were investigated by using downward traveling wave magnetic field,and the evolution law of θ phase was analyzed. The results show that the traveling wave magnetic field can refine the alloy structure to form fine near-equiaxed crystal structure, and improve the tensile strength and elongation of ZL205A alloy. Meanwhile, the excitation current of the magnetic field has a direct effect on the refinement effect of solidification structure. With the current frequency of 50 Hz, the desirable excitation current for ZL205A alloy is in range of 10~20 A. In addition, with the increase of the excitation current, the θ phase appears to be paramagnetic in the magnetic field. As the magnetic field increase, the nucleation undercooling degree is increased, so the nucleation rate is increased and θ phase is broken down. When the excitation current is less than 10 A, the electromagnetic force generated by the magnetic field has a great influence on the size of the θ phase. When the magnetic current is 20 A, the melt viscosity is increased as a result of the magnetic field Lorentz force, which can prevent the θ phase from further refinement.