In this article, structural features of Ti-TiB and (α+β) Ti alloys in the initial state, in the weld and in the heat-affected zone of electron beam welds were investigated. The influences of welding parameters, such as influence of the electron beam velocity, preheating of the welded alloys and the subsequent annealing of the welded joint on the its microstructure, and the mechanical strength and ductility of the critical elements of the joint were studied by scanning electron microscopy using microprobe Auger spectral and X-ray diffraction analysis and tensile tests. It has been shown that the conditions for rapid crystallization of the material from the melt of the weld contribute to refining of reinforcing fibers of TiB and its hardening in comparison with the starting material Ti-TiB. Besides that, influences of the preferential orientation of TiB reinforcing microfibers (along and across the welded butt joint) on the mechanical properties of the welded joint were investigated bz tensile testing. Using the methods of fractographic analysis, the effect of the boron-containing phase on the fracture character of Ti-TiB welded joints was established. It was shown that, along with the strengthening effect, TiB fibers cause embrittlement of the material.

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Analysis of fracture surfaces morphology of material of welded joints of Ti-TiB system alloys and (α + β) Тi alloy, obtained by electron-beam welding under various technological modes, is carried out. Parameters alterable were the electron beam displacement velocity and initial temperature of the parts welded. Prevalent effect of boron phase on fracture character of Ti-TiB system alloys and possibility of ductility increase both Ti-TiB system and (α+β Тi alloy, due to thermal effect action, is shown.

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