Corrosion Behavior of ECAP-Processed AM90 Magnesium Alloy

• Published in: Arabian journal for science and engineering (2011) 2018-09, Vol.43 (9), p.4871-4878
• Main Authors: Gopi, K. R., Nayaka, H. Shivananda, Sahu, Sandeep
• Format: Article
• Language: English
• Subjects: Charge transfer; Corrosion; Corrosion rate; Corrosion resistance; Corrosion resistant alloys; Corrosion tests; Electrochemical impedance spectroscopy; Engineering; Equal channel angular pressing; Grain refinement; Humanities and Social Sciences; Hydrogen evolution; Immersion tests (corrosion); Magnesium base alloys; Microstructure; multidisciplinary; Research Article - Mechanical Engineering; Science
• ISSN: 2193-567X; 1319-8025; 2191-4281
• DOI: 10.1007/s13369-018-3203-5

Magnesium AM90 alloy was subjected to equal-channel angular pressing (ECAP) using route B C . Microstructural characterization revealed refined grains having average grain size ∼ 3 μ m after ECAP 4 passes. Samples were subjected to electrochemical measurements to study the corrosion behavior. Potentiodynamic polarization test showed reduced corrosion current density ( I corr ) for processed samples up to ECAP 3 pass due to grain refinement. Electrochemical impedance spectroscopy showed an increase in the diameter of the capacitive arcs and charge-transfer resistance ( R t ) for ECAP-processed 3 pass sample indicating the reduction in corrosion rate. Increase in corrosion resistance is due to refined microstructure and uniform distribution of secondary particles forming a protective passivation layer ( Mg ( OH ) 2 ) on the sample’s surface. Immersion test indicated lower hydrogen evolution from ECAP-processed samples compared to the unprocessed condition indicating decreased corrosion rate.