Magnetic memory signal characteristic of metal under fatigue loading

Tensile fatigue experiments were performed to study the characteristic of temporary stable magnetiza-tion states under fatigue loading, as well as the distribution and variation of magnetic memory signal in the process of fatigue. Experimental results were analyzed and discussed using the modified J-A model. It is found that the temporary stable magnetization state of magnetic signal varies along a loop in a stress cycle and the loop changes when the fatigue load type changes, which indicates that it is reasonable using the modified J-A model to describe the magnetic memory phenomenon of metal. The change of magnetic signal is divided into three stages in the process of fatigue, which is explained according to the change law of parameter ξ″ (the parameter expresses the obstruction to magnetic domain wall motion) using the modified J-A model. The magnetic signal distributing in a ‘⌒’ shape around a defect is explained according to the distribution law of ξ″ around the defect.