磁场对过共晶Al-Fe合金中Al_3Fe相形态和分布的影响

Effect of Magnetic Field on the Morphology and Distribution of Al_3Fe Phase in Hypereutectic Al-Fe Alloy

研究了交流磁场(0.3 T)和直流强磁场(12 T)作用下Al-2.89%Fe合金中初生Al3Fe相的形态与分布的变化.结果表明,Al-2.89%Fe合金在无磁场和交流磁场下凝固时,大部分初生Al3Fe相沉积在试样下部.在交流磁场下凝固时,Al3Fe相变得细碎且向试样中心聚集,呈近金字塔状分布.在强磁场下凝固时,Al3Fe相所受磁力作用和重力作用相平衡,因而在整个试样中均匀分布,且沿着易磁化方向[121]发生定向排列.对磁场的作用机理进行了初步分析.

The changes in the morphology and distribution of the primary Al3Fe phase in Al-2.89%Fe alloy solidified in an AC magnetic field（0.3 T） and a high-intenisy DC magnetic field（12 T） were investigated.The results showed that the majority of primary Al3Fe phase is deposited on the sample bottom when the alloy solidified in or out of AC magnetic field.The Al3Fe phase was refined and accumulated towards the sample center to form a pyramid-like distribution in AC magnetic field.But,when the alloy solidified in a high magnetic field（12 T）,the Al3Fe phase is distributed uniformly in the whole sample because the magnetic force acted on it was balanced with the gravity force.Furthermore the Al3Fe phase aligned perpendicularly to the magnetic field direction with a preferred direction .The functional mechanism of the magnetic field was discussed.