The role of intermetallics on the corrosion initiation of twin roll cast AZ31 Mg alloy

S. Pawar; X. Zhou; G. E. Thompson; G. Scamans; Z. Fan

doi:10.1149/2.0291509jes

The role of intermetallics on the corrosion initiation of twin roll cast AZ31 Mg alloy

S. Pawar, X. Zhou, G. E. Thompson, G. Scamans, Z. Fan

Innoval Technology Limited

Research output: Contribution to journal › Article › peer-review

Abstract

The micro-galvanic coupling between the microconstituent phases and the α-Mg matrix in the twin roll cast AZ31 Mg alloy sheet of 6 mm thickness has been investigated using scanning Kelvin probe force microscopy (SKPFM) and electron microscopy. The β-Mg₁₇(Al,Zn)₁₂ phase at the interdendritic spaces, along with the Al₈Mn₅ particles with rosette/flower-shaped morphologies and Fe-particles have been observed in the surface/near-surface region of the alloy sheet. Volta potential differences exhibited by the microconstituents relative to the α-Mg matrix followed the order of Fe-particles > Al₈Mn₅ intermetallics > β-Mg₁₇(Al,Zn)₁₂ phase. The susceptibility to localized corrosion initiation by the intermetallics predicted from the SKPFM was confirmed by immersion testing conducted in naturally aerated 3.5% NaCl solution at ambient temperature.

Original language	English
Pages (from-to)	C442-C448
Journal	Journal of the Electrochemical Society
Volume	162
Issue number	9
DOIs	https://doi.org/10.1149/2.0291509jes https://doi.org/10.1149/2.0291509jes
Publication status	Published - 12 Jun 2015

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title = "The role of intermetallics on the corrosion initiation of twin roll cast AZ31 Mg alloy",

abstract = "The micro-galvanic coupling between the microconstituent phases and the α-Mg matrix in the twin roll cast AZ31 Mg alloy sheet of 6 mm thickness has been investigated using scanning Kelvin probe force microscopy (SKPFM) and electron microscopy. The β-Mg17(Al,Zn)12 phase at the interdendritic spaces, along with the Al8Mn5 particles with rosette/flower-shaped morphologies and Fe-particles have been observed in the surface/near-surface region of the alloy sheet. Volta potential differences exhibited by the microconstituents relative to the α-Mg matrix followed the order of Fe-particles > Al8Mn5 intermetallics > β-Mg17(Al,Zn)12 phase. The susceptibility to localized corrosion initiation by the intermetallics predicted from the SKPFM was confirmed by immersion testing conducted in naturally aerated 3.5% NaCl solution at ambient temperature.",

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AU - Pawar, S.

AU - Zhou, X.

AU - Thompson, G. E.

AU - Scamans, G.

AU - Fan, Z.

PY - 2015/6/12

Y1 - 2015/6/12

N2 - The micro-galvanic coupling between the microconstituent phases and the α-Mg matrix in the twin roll cast AZ31 Mg alloy sheet of 6 mm thickness has been investigated using scanning Kelvin probe force microscopy (SKPFM) and electron microscopy. The β-Mg17(Al,Zn)12 phase at the interdendritic spaces, along with the Al8Mn5 particles with rosette/flower-shaped morphologies and Fe-particles have been observed in the surface/near-surface region of the alloy sheet. Volta potential differences exhibited by the microconstituents relative to the α-Mg matrix followed the order of Fe-particles > Al8Mn5 intermetallics > β-Mg17(Al,Zn)12 phase. The susceptibility to localized corrosion initiation by the intermetallics predicted from the SKPFM was confirmed by immersion testing conducted in naturally aerated 3.5% NaCl solution at ambient temperature.

AB - The micro-galvanic coupling between the microconstituent phases and the α-Mg matrix in the twin roll cast AZ31 Mg alloy sheet of 6 mm thickness has been investigated using scanning Kelvin probe force microscopy (SKPFM) and electron microscopy. The β-Mg17(Al,Zn)12 phase at the interdendritic spaces, along with the Al8Mn5 particles with rosette/flower-shaped morphologies and Fe-particles have been observed in the surface/near-surface region of the alloy sheet. Volta potential differences exhibited by the microconstituents relative to the α-Mg matrix followed the order of Fe-particles > Al8Mn5 intermetallics > β-Mg17(Al,Zn)12 phase. The susceptibility to localized corrosion initiation by the intermetallics predicted from the SKPFM was confirmed by immersion testing conducted in naturally aerated 3.5% NaCl solution at ambient temperature.

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The role of intermetallics on the corrosion initiation of twin roll cast AZ31 Mg alloy

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The role of intermetallics on the corrosion initiation of twin roll cast AZ31 Mg alloy

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