Electrochemical dissolution behavior of cast and forged Ti2AlNb alloys in NaCl and NaNO3 electrolytes

Abstract

Although Ti2AlNb alloy has numerous exceptional properties that make it one of the most promising materials in the aerospace field, it also presents significant challenges to traditional machining. Nevertheless, electrochemical machining (ECM) presents distinctive advantages when it comes to processing difficult-to-cut materials. Regrettably, the electrochemical dissolution behavior of Ti2AlNb alloy has not been reported yet. In this study, the electrochemical dissolution behavior of forged and cast Ti2AlNb alloys in 10% NaCl and 20% NaNO3 electrolytes was systematically studied for the first time. In the same electrolyte composition, the passivation film formed on the forged Ti2AlNb alloy surface is thicker than that on the cast Ti2AlNb alloy surface, indicating higher corrosion resistance. Dissolution experiments were conducted on cube and rotary samples, followed by the assessment of surface quality using laser confocal microscopy. The experimental findings demonstrate that ECM in 10% NaCl electrolyte yields better surface quality for both Ti2AlNb alloys. The Ti2AlNb alloy in this study consists of the B2 phase and O phase, with preferential dissolution of the O phase observed during ECM.