The paper studies the effect of ultrasonic forging of the surface layers of linear friction welded joints of the VT8-1 titanium alloy on their fatigue life. Low-cycle fatigue tests report a 2.5-fold increase in the service life of the welded joint after ultrasonic forging of its surface layers. The fractographic analysis of the fracture surfaces shows that, after ultrasonic forging, cracks initiate from the lateral surface of a specimen and have a radial front without river markings and with scarcely visible tear ridges. The microrelief of the initiation and growth zone of the main crack indicates a more ductile pattern of the fatigue crack growth in the material after ultrasonic forging. Ultrasonic forging of the surface layers of the VT8-1 welded joint increases its fatigue life and presents an effective method for improving the service life of welded joints, thus excluding a complex thermomechanical treatment.
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