14MC21 NIGIS * CORCON 2014 * Nov 12 – 15, 2014 * Mumbai Stress Corrosion Cracking Study of a Wrought Mg-Mn Alloy Under Cathodic Charging Condition Bharat S. Padekar 1 1 Department of Mechanical Engineering, MIT Academy of Engineering, Alandi (D), Pune 412105, India. bharat.padekar@gmail.com V. S. Raja 2 2 Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, India. vsraja@iitb.ac.in ABSTRACT Stress corrosion cracking (SCC) behavior of a rare earth containing wrought Mg-Mn alloy was studied using cylindrical tensile specimens in 0.1 M NaCl solution saturated with Mg(OH) 2 using slow strain rate test. Glycerol was used as an inert environment, for comparison. Specimens were tested at open circuit potential and on continuous charging at ~300 mV cathodic with respect to the open circuit potential. The cathodic charging has been found to be to decrease the SCC susceptibility of the alloy, indicating that anodic dissolution could be one of the dominating mechanisms of SCC. Keywords: Mg-Mn magnesium alloy; slow strain rate test; cathodic charging INTRODUCTION Magnesium alloys are materials of choice for light weight applications, such as automotive and aerospace industries, as being only the 2/3 of the density of aluminium. Further, magnesium also offers advantages, such as castability, damping capacity, electromagnetic interference shielding, relatively high thermal and electrical conductivities, and recyclability making it a preferred choice [1]. The early magnesium alloys suffered rapid attack in moist conditions mainly due to the presence of impurities, notably, iron, nickel, and copper. These impurities or their compounds act as local cathodes in presence of a corroding environment. They create micro-cells with the anodic magnesium matrix. High purity alloys meant to counter this problem, are a relatively recent