On the relationship between grain boundary connectivity, coincident site lattice boundaries, and intergranular stress corrosion cracking

Lehockey, E. M.; Brennenstuhl, A.M.; Thompson, Ian

doi:10.1016/j.corsci.2004.01.019

Cited by 140 publications

(70 citation statements)

References 35 publications

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“…The estimated local plastic strain just shows the typical local misorientation that is observed under the plastic strain. Therefore, the local plastic strain is determined not only by applied plastic strain but also by geometry of grain structure [41,42], crystal orientation [23,43].…”

Section: Discussionmentioning

confidence: 99%

Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD

Jiang

Zhao

et al. 2015

Surface and Coatings Technology

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Q. (2015). Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD. Surface and Coatings Technology, Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD AbstractThis work presents a fine microstructure and local misorientation study of various oxide phases in the tertiary oxide scale formed on a hot-rolled steel strip via electron back-scattering diffraction (EBSD). Local strain in individual grains of four phases, ferrite (α-Fe), wustite (FeO), magnetite (Fe 3 O 4 ) and hematite (α-Fe 2 O 3 ), has been systematically analysed. The results reveal that Fe 3 O 4 has a lower local strain than α-Fe 2 O 3 , in particular, on the surface and inner layers of the oxide scale. The multiphase oxides along the cracking or α-Fe 2 O 3 penetration generally develop a high local misorientation. Localised stain along the cracks demonstrates that the misorientation tends to be strong near grain boundaries. The high fraction of small Fe 3 O 4 grains accumulate at the oxide-substrate interface, which leads to a dramatic increase in the intensity of local stain. This variation is due mainly to the phase transformation among the oxide phases, i.e., the Fe 3 O 4 particles during their nucleation and growth. The combined action of stress relief and re-oxidisation is proposed to explain the formation of Fe 3 O 4 seam at the oxide-steel interface. The present study offers an intriguing insight into the deformation behaviour of the tertiary oxide scale formed on steels, and may help with understanding the stress-aided oxidation effect of metal alloys. offers an intriguing insight into the deformation behaviour of the tertiary oxide scale formed on steels, and may help with understanding the stress-aided oxidation effect of metal alloys.

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Section: Discussionmentioning

confidence: 99%

Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD

Jiang

Zhao

et al. 2015

Surface and Coatings Technology

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“…2b) is, in presence of the strong texture component {001} parallel to the ND, as described in Section 3.1. This can be attributed to the fact that the refined grains grow surrounding the large grains to relieve the deformation during hot rolling, which is also associated with the grain sliding mechanism [35].…”

Section: Orientation Distributions Of Magnetite With Various Grain Sizesmentioning

confidence: 99%

Dependence of texture development on the grain size of tertiary oxide scales formed on a microalloyed steel

Jiang

Zhao

et al. 2015

Surface and Coatings Technology

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Q. (2015). Dependence of texture development on the grain size of tertiary oxide scales formed on a microalloyed steel. Surface and Coatings Technology, Dependence of texture development on the grain size of tertiary oxide scales formed on a microalloyed steel AbstractBoth orientational and geometrical characteristics of grains in tertiary oxide scales have been quantitatively investigated using the electron backscatter diffraction (EBSD) technique. Phase and orientation mappings demonstrate that the {001} planes of magnetite and the {0001} planes of hematite are parallel to the direction of oxide growth. Pole figures (PFs) as scattering plots clearly display the direct correlation between the orientations and microstructure sites of magnetite grains. Magnetite grains develop a strong rotated cube texture component that shifts to the {100} component, whereas those with the grain size of 1-5. μm develop the {001} cube texture component. The refined magnetite grains surrounding the abnormal ones can be a combined process, including magnetite pro-eutectoid during hot rolling and cooling and re-oxidation during air-cooling. Our findings offer insights toward further understanding of the link between the geometrical and orientation parameters of grains with respect to the deformation behaviour of oxide scales formed at elevated temperatures.

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“…The CSLBs are formed when the neighboring grains are in specific orientation relationships and have been shown to possess an increased resistance to SCC over HABs. [46][47][48][49][50][51][52] In addition, texture affects the high-temperature deformation behavior of a polycrystalline material and thus is expected to play a role in the SCC behavior as well. Figure 15 shows the grain-boundary character distribution (GBCD) of the weld alloys.…”

Section: Laboratory-prepared Alloysmentioning

confidence: 99%

“…Both these parameters are known to influence the SCC behavior of austenitic alloys in high-temperature water environments. [46][47][48][49][50][51][52] The OIM analysis allows a classification of boundaries according to the coincident site lattice model as either coincident site lattice boundaries (CSLBs) or high-angle boundaries (HABs). The CSLBs are formed when the neighboring grains are in specific orientation relationships and have been shown to possess an increased resistance to SCC over HABs.…”

Section: Laboratory-prepared Alloysmentioning

confidence: 99%

Crack growth rates and metallographic examinations of Alloy 600 and Alloy 82/182 from field components and laboratory materials tested in PWR environments.

Alexandreanu¹,

Chopra²,

Shack³

2008

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In light water reactors, components made of nickel-base alloys are susceptible to environmentally assisted cracking. This report summarizes the crack growth rate results and related metallography for field and laboratory-procured Alloy 600 and its weld alloys tested in pressurized water reactor (PWR) environments. The report also presents crack growth rate (CGR) results for a shielded-metal-arc weld of Alloy 182 in a simulated PWR environment as a function of temperature between 290°C and 350°C. These data were used to determine the activation energy for crack growth in Alloy 182 welds. The tests were performed by measuring the changes in the stress corrosion CGR as the temperatures were varied during the test. The difference in electrochemical potential between the specimen and the Ni/NiO line was maintained constant at each temperature by adjusting the hydrogen overpressure on the water supply tank. The CGR data as a function of temperature yielded activation energies of 252 kJ/mol for a double-J weld and 189 kJ/mol for a deep-groove weld. These values are in good agreement with the data reported in the literature. The data reported here and those in the literature suggest that the average activation energy for Alloy 182 welds is on the order of 220-230 kJ/mol, higher than the 130 kJ/mol commonly used for Alloy 600. The consequences of using a larger value of activation energy for SCC CGR data analysis are discussed.iv This page is intentionally left blank. Foreword vThis report presents crack growth rate (CGR) data and the results of the corresponding fracture surface and metallographic examinations from cyclic loading and primary water stress-corrosion cracking (PWSCC) tests of two nickel-base Alloy 182 (A182) weldments. These weldments are typical of those used in vessel penetrations and piping butt welds in nuclear power plants. The effect of crack orientation with respect to dendrite orientation is the most significant variable investigated in this study. However, this report also compiles data from other laboratories that describe the effects of material composition, loading characteristics, and chemistry of the aqueous environment. The PWSCC growth rates described for the A182 specimens in the report are comparable to the CGR that characterize the performance of Alloy 600 (A600).This report is one of a series of reports documenting the results of CGR testing in vessel head penetration materials. This report focuses on the Alloy 82 (A82) and A182 weld metals. This report also presents results from tests of the A600 base metal. The researchers tested (1) a laboratory-fabricated, shieldedmetal-arc deposit of A182; (2) a weldment sample from the J-groove weld of a control rod drive mechanism nozzle from the Davis-Besse Nuclear Power Plant; and (3) a hot leg nozzle-to-safe end weld from the Virgil C. Summer Nuclear Station.

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On the relationship between grain boundary connectivity, coincident site lattice boundaries, and intergranular stress corrosion cracking

Cited by 140 publications

References 35 publications

Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD

Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD

Dependence of texture development on the grain size of tertiary oxide scales formed on a microalloyed steel

Crack growth rates and metallographic examinations of Alloy 600 and Alloy 82/182 from field components and laboratory materials tested in PWR environments.

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