应力和晶粒组织对磁畴动态特性的影响

近年新兴的磁光成像技术，特别是磁畴动态特性可视化技术，为评估铁磁材料的应力状态提供了一种新的磁检测方法。为研究应力和晶粒组织/晶界对磁畴动态特性的影响，通过磁光成像装置，观测取向硅钢片在施加不同的应力和外加磁场时表面磁畴结构的变化。结果表明:应力作用下，附加磁畴数量减少，从点状附加磁畴转变为长条状主磁畴，且应力增加会使主磁畴平均宽度减小，主磁畴完全翻转所需要的磁场减小；外加磁场作用下，可使磁畴向磁场方向转动，磁场强度的增加，使与外加磁场同向的磁畴面积增加。同时，晶粒组织结构和内部的各向异性，以及晶界处的能量和钉扎作用，都会影响磁畴结构和磁畴壁的运动状态。研究结果有助于理清铁磁构件的磁弹耦合效应和磁检测技术的微观物理机制，为提高应力评估的灵敏度和可靠性提供重要的科学依据。

Effect of Stress and Grain Structures on Dynamic Properties of Magnetic Domains

Recently, emerging magneto-optical imaging technique, especially the visualization of the dynamic properties of magnetic domains, provides a new magnetic detection method for assessing the stress state in ferromagnetic materials. In order to investigate the influence of stress and grain structure/grain boundaries on the dynamic properties of the magnetic domains, a magneto-optical imaging system is used to observe the variations of magnetic domain structure of grain-oriented silicon steel sheets under different stresses and applied magnetic fields. The experimental results show that the number of additional domains decreases, which also changes from point-like lancet domains to sab-like domains under the stress. And with strengthened stress, the magnetic domain is refined, and its average width decreases. With external magnetic field, the magnetic domains are rotated to the direction of the magnetic field, alongside enlarged area of the domains parallel to the applied magnetic field. Moreover, the grain structure, internal magnetic anisotropy as well as pinning effect at grain boundaries can affect the magnetic domain structure and domain wall motion. The results help to clarify the magnetoelastic coupling effect of ferromagnetic components, and the microphysical mechanism of magnetic detection technology, thus providing an important scientific basis for improving the sensitivity and reliability of stress assessment.