Effect of simultaneous application of ultrasonic vibrations during laser surface melting on electrochemical properties of 2024 aluminum alloy
Sourabh Biswas, Sam Allison, S. Habib Alavi, and Sandip P. Harimkar
Volume 2, Issue 10, Page 675-678, Year 2017 | DOI: 10.5185/amp.2017/043
Keywords: 2024 aluminum alloy, corrosion, laser melting, ultrasonic vibrations.
Abstract: In the present investigation, effect of laser melting with and without simultaneous application of ultrasonic vibrations on electrochemical properties of 2024 aluminum alloy is investigated. The electrochemical behavior of the laser melted specimens was studied using open-circuit and potentiodynamic polarization measurements. Subsequently, investigation of the corrosion films was performed using scanning electron microscopy. It was observed that the laser melted specimens exhibited significant improvement in open circuit potential (both with and without simultaneous ultrasonic vibration application). The open circuit potential of the laser melted specimen without ultrasonic vibrations was observed to be more stable compared to the laser melted specimen with ultrasonic vibrations. It was observed that the corrosion mechanism undergoes a transition from pitting to uniform corrosion in the laser treated specimen, particularly in the laser melted specimen without ultrasonic vibrations. However, the extensive agitations due to ultrasonic vibrations in the melt pool appear to restrict Cu migration to grain boundaries that result in porous and relatively inefficient passive layer formation in laser processed samples with application of ultrasonic vibrations. This behavior was also observed in the potentiodynamic polarization studies that showed that the laser melted specimen without ultrasonic vibrations exhibited lower corrosion current and corrosion rate compared to the laser melted specimen with ultrasonic vibrations as well as the as received substrate. Copyright © 2017 VBRI Press.