研究了均恒磁场及梯度磁场条件下Sb-4.8%Mn亚共晶合金凝固组织的变化.结果表明, 在急冷条件下, 初 生Sb相呈小平面长大, 棱角分明;在无磁场条件下重熔凝固时, 初生Sb相的小平面特征消失, 棱角消失, 变为近球形. 在均恒磁场条件下重熔凝固时, 随着磁感应强度的增大,初生相呈现小平面趋势生长; 但磁感应强度增大到某一值时这种特征随之消失, 而且初生相的尺寸呈现先变大后变小的趋势. 在梯度磁场条件下, 磁感应强度B值以|BdB/dz|都较小的情况下, 正梯度对初生相有细化作用,负梯度使初生相粗化并呈现长条状. 随着磁感应强度B值及|BdB/dz|的增大, 上述现象变得不明显.强磁场可以使初生相的结晶温度提高, 减小熔体的过冷度,降低凝固速率.
The changes of solidified structures of Sb-4.8wt.%Mn hypoeutectic alloy under uniform and gradient magnetic fields were examined. It was found that the primary Sb phase in the alloy exhibited a change in growth behavior from a faced to non-faced one or from a non-faced to faced one. The faced/non-faced or non-faced/faced transition was found to be dependent on cooling rate and magnetic flux density. It was also found that the size of the Sb particles increased at first and then decreased with increasing magnetic flux density under uniform magnetic fields. Furthermore, the size of the Sb particles at a positive magnetic field gradient was found to be smaller than one at a negative magnetic field gradient when imposed upon magnetic field gradients with small absolute values of the product of the magnetic field flux density and its gradient. Thermal analyses of specimens indicated that the application of a high magnetic field decreased the undercooling of the primary arrest and the growth velocity of the primary Sb phase.The experimental results show that high magnetic fields can be used to control the morphology of the solidified structure and the size of the primary Sb phase in Mn-Sb hypoeutectic alloy.
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| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] |
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