The relation between severe plastic deformation microstructure and corrosion behavior of AZ31 magnesium alloy

Hamu, Guy Ben; Eliezer, D.; Wagner, Lothar

doi:10.1016/j.jallcom.2008.01.084

Cited by 393 publications

(119 citation statements)

References 21 publications

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“…Corrosion behavior has been investigated on UFG materials fabricated mainly by processing of SPD such as ECAP, ARB, HPT for aluminum and its alloy, [87][88][89][90][91][92][93]120,121,143,[150][151][152][153]156,[158][159][160][161][162][163][164][165][166][167][168][169][170][171] magnesium and its alloy, 34,72,[115][116][117]122,123,154,157,[172][173][174][175][176][177][178][179] copper and its alloy, 6,[96][97][98]…”

Section: General Descriptionmentioning

confidence: 99%

Corrosion of Ultrafine Grained Materials by Severe Plastic Deformation, an Overview

Miyamoto

2016

Mater. Trans.

110

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Corrosion of ultra ne grain (UFG) materials by severe plastic deformation (SPD) is reviewed in light of the existing literature and microstructural change. Fortunately, by holistic survey of the literature, it seems likely that grain re nement by SPD, while enhancing mechanical properties, does not compromise the overall corrosion resistance, and in many case, improve it in comparison with coarse-grained counterparts, although there are some contradictory results within the same materials and same environment. The degree of impact of UFG formation on corrosion is highest in stainless steels followed by aluminum and magnesium alloys whereas it is relatively marginal in pure copper and titanium. The effect of UFG formation by SPD on corrosion is imparted by not only grain re nement, but also other microstructural change occurring commonly in SPD in general and unique to each speci c SPD method. In this review, an attention is paid speci cally to the former case, and this includes shuf ing or redistribution of chemical inhomogeneity into a ner scale, deformation-induced grain boundaries and high internal stress stemming from these grain boundaries. The literature on stress corrosion cracking (SCC) of UFG materials are de nitely insuf cient to nd the general trends, more studies are waited.

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Section: General Descriptionmentioning

confidence: 99%

Corrosion of Ultrafine Grained Materials by Severe Plastic Deformation, an Overview

Miyamoto

2016

Mater. Trans.

110

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“…They observed a rather smooth surface with a smaller penetration rate at grain boundaries and thus considerable improvement in intergranular corrosion. For SPD materials, corrosion behavior such as general [10][11][12][13][14][15][16][17][18][19][20], intergranular [21][22][23] and pitting corrosion [21,[24][25][26][27][28][29][30][31][32] of UFG aluminum and aluminum alloy [17,21,22,24,25,[29][30][31][32], copper and copper alloy [11,15,19,28] as well as stainless steels [10,12,18,23,27] and magnesium [13,14,16,20] processed by SPD, and corrosive environment dependence [33][34]…”

Section: Introductionmentioning

confidence: 99%

Effects of Strain Energy and Grain Size on Corrosion Resistance of Ultrafine Grained Fe-20%Cr Steels with Extremely low C and N Fabricated by ECAP

Rifai

Miyamoto

Fujiwara

2015

International Journal of Corrosion

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Effect of strain energy and grain size on corrosion resistance of ultrafine grained (UFG) Fe-20%Cr steels with extremely low C and N fabricated by equal channel angular pressing (ECAP) was investigated. UFG structures of initial grain size of 144 nm exhibited the typical three-stage softening comprising recovery, recrystallization, and grain growth. Potentiodynamic polarization measurements were carried out with a conventional three-electrode cell to evaluate pitting potential. Pitting potential in 1000 mol⋅m −3 NaCl solution was nobler in UFG state, but pitting potential started to decrease monotonously at lower temperature compared to hardness. The degradation of corrosion resistance in the early stage of annealing is attributed to stability change of passivation by recovery of dislocation structures inside grains and in nonequilibrium grain boundaries. We therefore conclude that nobler potentials of UFG states were realized by not only grain size reduction but also defective deformation-induced UFG.

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“…Furthermore, a much more uniform protective passive layer was formed on the surface of the UFG sample, as shown in Figures 7b and 8b. The effective role of the grain-size refinement on the enhancement of the corrosion behavior has been previously reported [58][59][60][61]. It has been shown that the ultrafine grains improve the activity of electrons at grain boundaries leading to the decrease in the electron work function [62].…”

Section: Discussionmentioning

confidence: 97%

Significant Corrosion Resistance in an Ultrafine-Grained Al6063 Alloy with a Bimodal Grain-Size Distribution through a Self-Anodic Protection Mechanism

Oskooie

Asgharzadeh

Sadighikia

et al. 2016

Metals

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Abstract:The bimodal microstructures of Al6063 consisting of 15, 30, and 45 vol. % coarse-grained (CG) bands within the ultrafine-grained (UFG) matrix were synthesized via blending of high-energy mechanically milled powders with unmilled powders followed by hot powder extrusion. The corrosion behavior of the bimodal specimens was assessed by means of polarization, steady-state cyclic polarization and impedance tests, whereas their microstructural features and corrosion products were examined using optical microscopy (OM), scanning transmission electron microscopy (STEM), field emission scanning electron microscopy (FE-SEM), electron backscattered diffraction (EBSD), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) techniques. The bimodal Al6063 containing 15 vol. % CG phase exhibits the highest corrosion resistance among the bimodal microstructures and even superior electrochemical behavior compared with the plain UFG and CG materials in the 3.5% NaCl solution. The enhanced corrosion resistance is attributed to the optimum cathode to anode surface area ratio that gives rise to the formation of an effective galvanic couple between CG areas and the UFG matrix. The operational galvanic coupling leads to the domination of a "self-anodic protection system" on bimodal microstructure and consequently forms a uniform thick protective passive layer over it. In contrast, the 45 vol. % CG bimodal specimen shows the least corrosion resistance due to the catastrophic galvanic corrosion in UFG regions. The observed results for UFG Al6063 suggest that metallurgical tailoring of the grain structure in terms of bimodal microstructures leads to simultaneous enhancement in the electrochemical behavior and mechanical properties of passivable alloys that are usually inversely correlated. The mechanism of self-anodic protection for passivable metals with bimodal microstructures is discussed here for the first time.

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The relation between severe plastic deformation microstructure and corrosion behavior of AZ31 magnesium alloy

Cited by 393 publications

References 21 publications

Corrosion of Ultrafine Grained Materials by Severe Plastic Deformation, an Overview

Corrosion of Ultrafine Grained Materials by Severe Plastic Deformation, an Overview

Effects of Strain Energy and Grain Size on Corrosion Resistance of Ultrafine Grained Fe-20%Cr Steels with Extremely low C and N Fabricated by ECAP

Significant Corrosion Resistance in an Ultrafine-Grained Al6063 Alloy with a Bimodal Grain-Size Distribution through a Self-Anodic Protection Mechanism

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