Study on corrosion fatigue behavior of heavy piece Ti6Al4V titanium EBW joint in artificial seawater

Abstract

Titanium alloy has been more and more used in the ocean engineering field. Since the crucial service environment, the corrosion fatigue behavior of the Ti6Al4V alloy EBW joint has been investigated and analyzed. The results show that the grain size of the molten zone decreases gradually from the central line to the base metal symmetrically and the acicular α’ martensite and β phase grain boundaries are the dominating phases of the seam zone. Moreover, the corrosion fatigue crack growth rate of the seam zone was insensitive to the texture of the base metal and crystal orientation of the ti6al4v alloy. It could also be seen that the base metal and the seam zone have different crack growth mechanisms, which is mainly during to the existence of the acicular α‘ martensite in the seam zone and the trend of crack tip energy release. The crack propagation rate of the seam is lower than that of the base metal.