Formation of Residual Stresses in the Surface Layers of Titanium Alloy Targets Irradiated with High-Current Pulsed Electron Beams

X-ray diffraction analysis, optical metallography, and transmission electron microscopy demonstrated that irradiation with high-current pulsed electron beams in the melting mode leads to formation of residual compressive stresses and a finely dispersed globular-lamellar microstructure (the α, α', and α'' plates being oriented parallel or nearly parallel to the surface) in the near-surface layer of samples of VT6 and VT8 alloys up to 20 μm thick. These phenomena are expected to increase the fatigue strength of the material during bending tests. Meanwhile, residual tensile stresses are formed on the surface of samples of VT9 alloy at any energy density of electron beams; vacuum annealing is required to remove these stresses.