Corrosion Behavior and Prediction of Rolled/Additive Manufactured Ti-6al-4v Joints in Seawater Environment

Abstract

The rolling-additive hybrid manufacturing technology (RAHM) can achieve the greatest balance between molding efficiency and cost of Ti-6Al-4V. Welding used to connect different components in the RAHM is unavoidable. The corrosion behavior and prediction of welded joints are crucial for assessing the reliability of underwater equipment. In this paper, the laser metal deposition (LMD) additive manufacturing Ti-6Al-4V alloy was successfully connected with the rolling Ti-6Al-4V plate by electron beam welding (EBW). Then the corrosion behavior of welded joints was investigated through immersion experiments, electrochemical corrosion experiments and microstructural characterization. Finally, a corrosion model was established based on the corrosion behavior and corrosion parameters of the welded joints. The results show that non-uniform corrosion occurs on welded joints in seawater environment. The corrosion resistance of welded joints is primarily influenced by grain orientation, phase composition, surface microstructure, and grain boundary angles. The model predicted the corrosion depth of the welded joints at 150 and 200 days. The error was within 20% compared with the experimental results, which verified the scientific validity and accuracy of the model.

Keywords: rolling-additive hybrid manufacturing, electron beam welding, Corrosion behavior, prediction