AZ80-1Y镁合金在低频电磁铸造过程中的传热行为

摘要

Heat transfer behaviors of AZ80−1%Y alloy during low frequency electromagnetic casting (LFEC) and direct chilling casting were studied by in-situ temperature measurement. The results demonstrated that the low frequency electromagnetic field (EM) caused forced convection in the melt during LFEC. The forced convection led to uniform solidification velocity and temperature field. EM frequency, excitation current intensity and casting temperature could control the heat transfer behavior. The forced convection could improve the microstructure and degrade the difference in microstructure between the edge and center of billet. Appropriate parameters of low frequency EM for casting Mg alloy are 20 Hz of frequency and 60 A of electric current intensity.%利用原位测温手段研究 AZ80−1%Y 镁合金在低频电磁铸造和直冷铸造中的传热行为。结果表明，在低频电磁铸造过程中，低频电磁场使熔体产生强制对流，从而使凝固速度和温度场更加均匀。强制对流还可有效地改善锭坯的微观组织并降低锭坯边部和中心组织的不均匀性。电磁场的频率、励磁电流和铸造温度均对传热行为有较大的影响。对于实验合金，理想的电磁参数为频率20 Hz和励磁电流60 A。