Increasing the Fatigue Durability of an 3D-Printed Ti-6Al-4V Alloy Electron-Beam Welded Joint by Ultrasonic Electropulsing Shock Treatment

It has been shown by X-ray diffraction that the ultrasonic electropulsing shock treatment of specimens with a Ti-6Al-4V alloy weld joint formed by the electron-beam wire additive technology with the use of a hard-alloy (Co-WC) striker leads to an increase in the volumetric content of the beta-phase, the formation of Ti-Co and Ti-Co-Al intermetallide phases, an increase in the microhardness, and a 1.5-fold increase in fatigue durability compared to the initial state. After treatment, elastic compression macrostresses appear in the surface specimen layers to become higher in the basic material zone compared to the joint area. An increase in the fatigue durability of specimens with a weld joint after treatment is caused by the essential reinforcement of their surface layers due to the formation of intermetallide phases. The destruction of a specimen with a weld joint occurs after treatment in the joint area. Fracturing has been characterized as brittle in the surface layers of a specimen and as a predominantly viscous dimple far from its surface.