Mechanical properties of Ti6.5Al2Zr1Mo1V titanium alloy with EBW under different temperatures

With the development of welding technology, electron beam welding (EBW) is manufacturing the aero parts with heavy thickness. To improve welding quality and mechanical property, we employed EBW with beam oscillation on Ti6.5Al2Zr1Mo1V alloy with 60 mm thickness, and observed the weld microstructures after X-ray NDT, and conducted the tensile and impact tests under different temperatures. The results showed the crystals of the welds were fringe, and the microstructures of the welds were acicular α′ martensite. The acicular and isometric crystals existed in HAZ, which were α′ martensite mixed with α+β structure. With the increase of the temperatures, tensile properties of the top and bottom joints gradually lowered, and the strengths were almost equal to base metal, and the percentage elongations after fracture were lower than those of base metals. The strength overmatching of the joints resulted in the inhomogeneous elastic-plastic deformations, and tensile specimens of the joints ruptured in base metal. The impact toughnesses of top welds were equal to the bottoms under different temperatures, which were lower than those of base metals. Electron beam oscillation improved the uniformity of the microstructures, which contributed to the homogeneity of mechanical properties from the top to bottom joints.