Nb元素的添加对Fe-Co-2V软磁合金微观结构的影响

Fe-49Co-2V与Fe-49Co-2V-0.3Nb合金经热轧、冷轧制成带材,之后在850 ℃进行2 h退火热处理。使用透射电镜和选区电子衍射对合金微观组织结构进行观察,结果表明Nb元素的添加促进了析出相的形成,析出相为Nb与Co、Fe组成的小尺寸晶粒,不含V元素,其化学式为Co₃Nb,其中部分Co原子被替换为Fe原子。在铸态样品中同样发现了形态不同的析出相,推测可能是带材中析出相的来源。在添加Nb元素的合金中发现条纹状孪晶结构且集中于析出相附近,推测可能与合金伸长率升高及晶粒细化有关。

Effect of Nb addition on microstructure of Fe-Co-2V soft magnetic alloy

Fe-49Co-2V and Fe-49Co-2V-0.3Nb alloys were hot and cold rolled into sheets respectively,then annealed at 850 ℃ for 2h.The microstructure of the alloys was investigated by means of transmission electron microscope( TEM) and selected area electron diffraction( SAED). The results show that the adding of Nb facilitates the formation of precipitates,which is small particles composed with Nb,Co and Fe,while V is not detected. The chemical formula of the precipitate is Co3Nb,in which some Co atoms are partly substituted by Fe atoms.The precipitates in different shapes are also detected in as-cast specimens which might be the source of precipitates in the sheet specimens.In addition,lath-like twin structures are detected closing to the precipitates in the alloy containing Nb,which might be beneficial to the improvement of ductility and grain refinement.