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对比研究了未处理、直流磁场处理、脉冲磁场处理及直流-脉冲复合磁场处理对长周期结构增强Mg97Y2Cu1合金凝固组织的影响,并研究了复合磁场处理条件下不同的脉冲磁感应强度、脉冲频率、模具预热温度及浇注温度下合金的晶粒大小。结果表明,经复合磁场处理后,合金的凝固组织明显改善,其效果好于单一的直流磁场处理或脉冲磁场处理;合金的初生相转变为细小的等轴晶或蔷薇状晶,第二相分布变得均匀和连续,体积分数提高。当脉冲磁感应强度在0~0.25T、脉冲频率在1~10Hz范围内,随着脉冲磁感应强度或脉冲频率的增大,合金的晶粒尺寸逐渐减小。在20~600℃范围内,随着模具预热温度提高,合金的晶粒尺寸先减小后有所增大;在650~750℃范围内,随着浇注温度的提高,合金的晶粒尺寸先增大后减小。
The effects of untreated, DC magnetic field, pulsed magnetic field and DC-pulsed magnetic field on the solidification microstructure of Mg97Y2Cu1 alloy strengthened by long-period structure were studied. The effects of different magnetic flux density, pulse frequency, Preheat temperature and pouring temperature alloy grain size. The results show that the solidified microstructure of the alloy is obviously improved after the composite magnetic field treatment, and the effect is better than the single DC magnetic field treatment or pulsed magnetic field treatment. The primary phase of the alloy transforms into small equiaxed or rosette crystals. The second phase distribution Become even and continuous, the volume fraction increases. When the pulse magnetic flux density is in the range of 0 ~ 0.25T and the pulse frequency is in the range of 1 ~ 10Hz, the grain size of the alloy decreases with the increase of the pulse magnetic induction intensity or pulse frequency. In the temperature range of 20 ~ 600 ℃, the grain size of the alloy decreases first and then increases with the increase of the preheating temperature. With the increase of pouring temperature, the grain size of the alloy First increase and then decrease.