Study on the Strength and Plastic Toughness Control Technology of Electron Beam Welding Joint of Titanium Alloy

Electron beam welding of titanium alloy is easy to get high strength welded joints generally. Due to the lack of ductility and toughness, the joint often becomes a failure, which seriously affects the safety of electron beam welded components. This work is aiming at investigation on the strength and toughness control technology of Ti6Al4V alloy joints by electron beam welding with three filler materials to achieve equal strength matching welded joints with good plasticity. The results showed that the microstructures of three filling material are composed of Widmanstatten microstructure and alpha. The uniformity of microstructure and microhardness of fusion zone have been studied. The tensile strength and impact toughness have been researched, and the fracture morphology was observed by scanning electron microscopy. The strength of adding pure titanium joints decreased with the increase in the thickness of the joint. At the same thickness, the addition of Al can ensure the increase in plasticity and decrease the strength. Therefore, adding 0.5 mm pure titanium and 1 mm Ti4Al in sheet can obtain the joint with the same strength as the base metal and higher toughness than the base metal, and both fillers can realize the effective control of joint strength and toughness. The uniformity of microstructure and microhardness of joints adding 1 mmTi4Al is better.