Bimodal grain size distribution: an effective approach for improving the mechanical and corrosion properties of Fe–Cr–Ni alloys

Mahesh, B.V.; Raman, R.K. Singh; Koch, Carl C.

doi:10.1007/s10853-012-6686-6

Cited by 32 publications

(24 citation statements)

References 35 publications

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“…Resistance to corrosion of stainless steel was reportedly enhanced by UFG formation by SPD [27,36,37]. This is often explained by the higher diffusion of Cr enhanced by high density of grain boundaries [53][54][55].…”

Section: Discussionmentioning

confidence: 99%

“…When the precipitation becomes smaller than critical size, it does not work as cathode site for pitting formation [30]. For FeCr steels in which passivation occurs by Cr elements, pitting corrosion resistance is enhanced by UFG formation by SPD 2 International Journal of Corrosion because Cr diffusion to the surface is enhanced by the high density of dislocations and grain boundaries and promotes passivation [12,27,36,37].…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

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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“…12. The researchers 68 ± 70 paid special attention to preparation and certification of initial samples, which were obtained by mechanosynthesis followed by hot compaction and sintering (iron alloys) 68,69 or electrodeposition (pure nickel). 70 The grain size was controlled by annealing, whereas structural bimodality (simultaneous presence of nano-and micrograins) 68, 69 was achieved by mixing powders with nano-and micrograins.…”

Section: Oxidation Of Nanomaterialsmentioning

confidence: 99%

Thermal stability of consolidated metallic nanomaterials

Andrievski¹

2014

Russ. Chem. Rev.

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“…Nevertheless, the corrosion behavior of bimodal microstructures has been infrequently noticed and requires further attention. To the best of our knowledge, the only related study in this field has been carried out by Mahesh et al [23] reporting the hot oxidation behavior of bimodal Fe-10Cr-5Ni-2Zr (in wt. %) alloy (as a nonpassivable alloy).…”

Section: Introductionmentioning

confidence: 99%

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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Bimodal grain size distribution: an effective approach for improving the mechanical and corrosion properties of Fe–Cr–Ni alloys

Cited by 32 publications

References 35 publications

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

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

Thermal stability of consolidated metallic nanomaterials

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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