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研究了低频交变磁场下Cu-14Fe原位复合材料的凝固行为,讨论了磁场施加和磁场强度对铸锭组织、溶质分布和性能的影响。结果表明,Cu-14Fe复合材料常规凝固组织中Fe相主要呈枝晶和不规则长条状分布,施加交变磁场后,Fe相转化成梅花状或等轴状晶粒,分布更均匀。交变磁场的施加导致Cu基体中Fe溶质含量降低,磁场强度越大,浓度下降越明显。交变磁场的施加大幅降低了铸锭中的氧含量,提高了材料的电导率,降低了基体硬度。交变磁场对Cu-14Fe原位复合材料凝固过程的影响分别从动力学和热力学方面进行了分析,磁场一方面通过力场改变了熔体的热流和溶质分布,另一方面作为能量场作用于熔体影响了晶胚形核的势垒,从而影响了Cu-14Fe原位复合材料的凝固组织与性能。凝固过程中施加交变磁场有利于Cu-14Fe原位复合材料中Fe相的细化和析出。
The solidification behavior of Cu-14Fe in-situ composites under alternating low-frequency magnetic field was studied. The effect of magnetic field and magnetic field on the microstructure and solute distribution and properties of ingot was discussed. The results show that the Fe phase in the Cu-14Fe composite is mainly dendritic and irregularly elongated. After the alternating magnetic field is applied, the Fe phase is transformed into plumule or equiaxed grains with more uniform distribution. The application of alternating magnetic field leads to the decrease of Fe solute content in Cu matrix. The greater the magnetic field strength, the more obvious the drop of concentration. The application of alternating magnetic field greatly reduces the oxygen content in the ingot, improves the electrical conductivity of the material and reduces the hardness of the matrix. The effects of alternating magnetic field on the solidification process of Cu-14Fe in-situ composites were analyzed respectively from the aspects of dynamics and thermodynamics. On the one hand, the magnetic field changed the heat flux and solute distribution of the melt through the force field and on the other hand, The melt affects the barrier of nucleation of the embryo, which affects the solidification structure and properties of Cu-14Fe in-situ composites. The application of alternating magnetic field during solidification is beneficial to the refinement and precipitation of Fe phase in Cu-14Fe in-situ composites.