Microscopic mechanism of the combined magnetic-vibration treatment for residual stress reduction

This study proposes a new technology for reducing residual stress using a combined magnetic–vibration treatment. To study the combined reduction effect of magnetic and vibration treatments, the independent reduction effects of vibration and magnetic technology were compared. To study the effect of vibration, magnetic, and combined magnetic-vibration treatments on the residual stress in silicon steel, the change in the mesoscopic structure was studied using electron backscatter diffraction (EBSD). The microstructures of the materials were studied using residual stress measurements, transmission electron microscopy (TEM) observations, X-ray diffraction (XRD) analysis, and magnetic domain observations. The experimental results reveal that all three methods reduced the residual stress, among which the combined magnetic-vibration treatment was the best, and the effect of the composite treatment was greater than the sum of the effects of the individual treatments. All three methods reduced the residual stress by providing energy to increase the movement of dislocations in the material and cause dislocation slip. Compared with the other two methods, the combined magnetic-vibration treatment promoted the transformation of magnetic domains into uniform layered domains and excited dislocation movement in more regions to reduce residual stress. However, after all three types of reduction techniques, the mesoscopic structure, such as grain size and texture, was not significantly affected.