Influence of Vanadium Element on Microstructure of Electron Beam Welded Titanium Alloy to Stainless Steel Joint

Electron beam welding experiments of titanium alloys with different vanadium content to stainless steel, as well as alpha titanium to stainless steel using vanadium sheets as filler metal and transition portion were carried out. Microstructures of the joints were examined by scanning electron microscope. The properties were evaluated by microhardness and tensile strength. It was shown that electron beam welding is not feasible due to the brittle Ti-Fe intermetallics with high hardness. Increase of vanadium content in base metal can restrain but can't avoid the formation of cracks. When vanadium content was too large, the joint was embrittled by FeTi compound with supersaturated V and also cracked after welding. Crack free joint was achieved by using vanadium transition portion which can prevent the contact of Ti and Fe elements. However, the formation of brittle a intermetallics reduced the tensile strength of the joint, only up to 134MPa.