TY - JOUR
T1 - Enhanced corrosion resistance of AZ91 alloy produced by semisolid metal processing
AU - Mingo, B.
AU - Arrabal, R.
AU - Mohedano, M.
AU - Pardo, A.
AU - Matykina, E.
AU - Rivas, A.
PY - 2015/1/29
Y1 - 2015/1/29
N2 - Rheocast AZ91 magnesium alloy was evaluated in terms of microstructure and corrosion resistance. Rheocasting leads to a globular microstructure of α-Mg spheres separated by an interconnected β-Mg17Al12 (β-phase) network. Findings revealed that early stages of corrosion were located at the center of α-Mg globules and more importantly at α-Mg/β-phase interfaces due to galvanic coupling as predicted from surface potential maps. Electrochemical, hydrogen evolution and weight loss measurements demonstrated the superior corrosion resistance of the rheocast alloy. This was attributed to an improved barrier effect of the β-Mg17Al12 phase and, possibly, to a smaller area fraction of Al-(Mn, Fe) inclusions. For long immersion times, only small attacked areas were observed which corresponded to randomly corroded α-Mg globules.
AB - Rheocast AZ91 magnesium alloy was evaluated in terms of microstructure and corrosion resistance. Rheocasting leads to a globular microstructure of α-Mg spheres separated by an interconnected β-Mg17Al12 (β-phase) network. Findings revealed that early stages of corrosion were located at the center of α-Mg globules and more importantly at α-Mg/β-phase interfaces due to galvanic coupling as predicted from surface potential maps. Electrochemical, hydrogen evolution and weight loss measurements demonstrated the superior corrosion resistance of the rheocast alloy. This was attributed to an improved barrier effect of the β-Mg17Al12 phase and, possibly, to a smaller area fraction of Al-(Mn, Fe) inclusions. For long immersion times, only small attacked areas were observed which corresponded to randomly corroded α-Mg globules.
UR - http://www.scopus.com/inward/record.url?scp=84923360468&partnerID=8YFLogxK
U2 - 10.1149/2.0521504jes
DO - 10.1149/2.0521504jes
M3 - Article
AN - SCOPUS:84923360468
SN - 0013-4651
VL - 162
SP - C180-C188
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
IS - 4
ER -
