Abstract：Titanium alloy is subject to cyclic load for a long time in service, and the components are prone to fatigue fracture. Fatigue monitoring of titanium alloy structure is of great significance to industrial safety. In this paper, a fatigue monitoring method combined with weak magnetic field measurement is proposed. On the basis of weak magnetic testing technology, the force magnetic model of weak magnetic monitoring is put forward, the standard tensile test block is made, the weak magnetic monitoring system and fatigue test system are used for fatigue monitoring test, and the lattice constants before and after fatigue were measured. The results show that the change of magnetic signal in fatigue test has good coincidence and consistency with the fatigue process, and the magnetic signal in the most extended stage of fatigue life keeps stable and small amplitude fluctuation, and finally the magnetic signal rises sharply in the transient area. In the last stage of fatigue, the sample in the stage of instantaneous fracture is fractured, and the monitoring magnetic curve is greatly enhanced. The curve results are consistent with the force and magnetic model, the cross-section of the magnetic line of force in the vertical direction increases, and the magnetic signal is enhanced when the cell is compressed. It has been proven that it is feasible to monitor the fatigue of titanium alloy with weak magnetic field.
2020, 
