Stress Corrosion Cracking of Rare- Earth Containing Magnesium Alloy EV31A Compared With AZ91E Using Slow Strain Rate Test Bharat S. Padekar IITB-Monash Research Academy IIT Bombay Powai, Mumbai-400076 India V. S. Raja Department of Metallurgical Engineering and Materials Science Indian Institute of Technology Bombay Mumbai-400076 India R. K. Singh Raman Department of Mechanical & Aerospace Engineering & Department of Chemical Engineering Monash University, Clayton Melbourne, Victoria 3800 Australia Lyon Paul Magnesium Elektron Ltd Manchester United Kingdom ABSTRACT Stress corrosion cracking (SCC) of the high performance rare-earth (RE) containing magnesium alloy Elektron 21 (ASTM - EV31A) was studied using slow strain rate test (SSRT). Glycerol, distilled water, and 0.01 N and 0.1 N NaCl solutions saturated with Mg(OH) 2 were employed. For comparison a well- known AZ91E alloy was also studied. SSRT studies indicate that both the alloys were susceptible to SCC to some extent in 0.1 N, 0.01 N NaCl solutions and distilled water. However, EV31A showed higher SCC resistance than AZ91E. The fractography of SSRT tested AZ91E and EV31A specimens were largely found to be transgranular (TGSCC) in distilled water. However in 0.1 N and 0.01 N NaCl solutions AZ91E exhibited transgranular, while EV31A showed mixed TGSCC and intergranular (IGSCC) fracture involving hydrogen embrittlement. EV31A showed lower susceptibility to SCC in all the three solutions than AZ91E, that is there is not much loss in mechanical properties of EV31A as compared to that of AZ91E in these environments. Key words: EV31A - magnesium alloy; stress corrosion cracking and slow strain rate test. ©2012 by NACE International. Requests for permission to publish this manuscript in any form, in part or in whole, must be in writing to NACE International, Publications Division, 1440 South Creek Drive, Houston, Texas 77084. The material presented and the views expressed in this paper are solely those of the author(s) and are not necessarily endorsed by the Association. C2012-0001556