Influence of Constant Magnetic Field upon Fatigue Life of Commercially Pure Titanium

Cyclic tests of the multicycle fatigue of commercially pure titanium were performed under normal conditions (without a magnetic field) and after exposure to a constant magnetic field of varying density (B = 0.3, 0.4, 0.5 T). It was shown that the application of the constant magnetic field of varying density led to a fold increase in the average number of cycles to destruction of the VT1-0 titanium samples by 64, 123, and 163%, respectively. Scanning electron microscopy revealed that the magnetic field led to a 1.45-fold increase in the critical length of the fracture (the width of the fatigue crack growth zone) and a 1.6-fold decrease in the distance between the fatigue striations in the accelerated crack growth zone of the destroyed titanium samples. It was established that a subgrain (fragmented) structure formed in the area of the fatigue growth of the fracture of the titanium samples. The size of the subgrains corresponded to the spaces between the fatigue striations, which had an inhibitory influence on the microcrack propagation. Collectively, the revealed facts are indicative of a higher material resistance to fatigue fracture propagation and increased operation resources under the fatigue tests in the magnetic field, which correlates with the data on the growth of the average number of cycles to fracture of the VT1-0 titanium samples.