Investigation of corrosion and metallurgical characteristics of friction stir-welded magnesium alloy welds under immersion, salt fog, pitting and galvanic corrosion tests

¹ Department of Mechanical Engineering, Sri Ramanujar Engineering College, Vandalur, 600 048 Chennai, Tamil Nadu, India
e-mail: sridhanapal2010@gmail.com
² Department of Mechanical Engineering, College of Engineering, Guindy, Anna University, 600 025 Chennai, Tamil Nadu, India
³ Center for Materials Joining & Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalainagar, 608 002 Chidambaram, Tamil nadu, India

Received: 5 November 2012
Accepted: 29 October 2013

Abstract

An investigation was carried out to quantify and characterize the corrosion behavior of AZ61A magnesium alloy joints. Extruded 6-mm-thick Mg alloy plates of AZ61A grade were butt-welded using a solid-state, environmentally cleaner welding process, the friction stir welding process. The weld specimens underwent immersion, salt spray, pitting and galvanic corrosion tests in order to quantify and characterize the corrosion rates of the welds with the influence of different pH values, chloride ion concentrations and the corrosion time. The corrosion rates, microstructure, scanning electron microscopy and X-ray diffraction analysis concluded the optimum parameters for the usage of the magnesium alloy welds for the best service applications.