Plastic deformation and fatigue damage, as the typical micro-damage caused by external loads such as earthquake and long-term process of liquid flow/stress, may seriously affect the material electromagnetic properties and shorten the structural lifespan. In this paper, first, the correlation between the material electromagnetic properties and the plastic deformation is investigated for a 304 austenitic stainless steel, and the mechanism is discussed based on the microstructure analysis. It is indicated that the increasing of plastic deformation leads to the material conductivity decrease which is considered to relate to the micro-defects including slip and twins, while the increasing of plastic deformation leads to the material magnetic property increase that has a close relationship with the martensitic transformation. Moreover, the influence of fatigue damage on the material electromagnetic properties and the microstructure analysis (slips, twins, and martensitic transformation) are also confirmed. Finally, the combined effect of plastic deformation and fatigue damage is also investigated through experiment. Besides, the difference of microstructures of three kinds of damage specimens is observed and analyzed.
- 304 austenitic stainless steel
- fatigue damage
- magnetic permeability
- nondestructive evaluation
- plastic deformation