Experimental Study On The Stress And Magnetic Behavior Of Non-ferromagnetic Materials In Non-magnetic Space

The fracture cases of large non-ferromagnetic components which caused by static loading or cyclic loading in the long-time running are very common,therefore,it is particularly important to study the damage monitoring for non-ferromagnetic materials.In view of this situation,a damage monitoring technique for nonferromagnetic materials was proposed in this paper.This paper firstly described the mechanical behavior and the microscopic changes of the materials under stress,and the feasibility of the weak magnetic monitoring technology for the monitoring of the fracture of the non-ferromagnetic materials was demonstrated by combining the theory of weak magnetic monitoring principle.According to the change of the magnetic induction intensity on the surface of non-ferromagnetic materials which caused by the stress in the geomagnetic field,the hypothesis that stress induced magnetic phenomenon of the non-ferromagnetic materials was firstly put forward.The stress magnetic monitoring system was set up and the stress magnetic tests were conducted under the non-magnetic space by using7075 aluminum alloy and H62 brass alloy as the experimental materials.By monitoring the changes of the stress,strain and the magnetic field intensity of the sample surface during the tests,the stress induced magnetic phenomenon was verified.Besides,the changes of microstructure and magnetic properties of the samples before and after the test were measured and analyzed.The results of the microstructure testing showed that the lattice constant of the samples changed during the testing;and the results of the magnetic characteristics testing showed that the magnetic susceptibility of the samples also changed due to the effect of the stress.At last,according to the measured performance parameters,the change of magnetic field intensity was analyzed,and the relationship between the change of mechanical properties and the change of magnetic properties was explored.Among them,In the relationship between stress,strain and magnetic field strength,it is found that the variation law of the surface magnetic field intensity is consistent with the change rule of stress,and there was a positive correlation between the change of magnetic field intensity and dd /??,then the possible relationship model between them was put forward,which provided the experimental basis for the application of weak magnetic monitoring technology in the monitoring of non-ferromagnetic materials.