4.7 Article

Model of vacancy diffusion-assisted intergranular corrosion in low-alloy steel

Journal

ACTA MATERIALIA
Volume 220, Issue -, Pages -

Publisher

PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2021.117348

Keywords

Pipeline steel; Intergranular corrosion; Stress corrosion cracking; Vacancy; Mathematical model

Funding

  1. U.S. Department of Transportation, Pipeline and Hazardous Materials Safety Administration [DTPH5614HCAP01, 693JK31950003CAAP]

Ask authors/readers for more resources

The paper presents a model for intergranular corrosion of nonsensitized low-carbon pipeline steels, where enhanced grain boundary oxidation is explained by vacancies produced by reactive Si atoms. Experimental evidence supports the role of vacancy diffusion in the evolution of IGC, with calculations showing agreement with experimental measurements. The rationalization of sharpening of GB grooves over time during corrosion exposures and the quantitative explanation of IGC enhancement by vacancy diffusion without solute segregation or precipitation at GBs are key findings.
A model is presented for intergranular corrosion (IGC) of nonsensitized low-carbon pipeline steels, in which enhanced grain boundary (GB) oxidation is enhanced by vacancies produced by oxidation of re-active Si atoms. Evidence for vacancy injection at corroding GBs had been provided by recent nanoin-dentation measurements. Model calculations of IGC evolution controlled by lattice vacancy diffusion are compared to experimental measurements. Realistic dihedral angles of corroded GB grooves are predicted based on a vacancy diffusivity within the range of values expected for bcc iron. The calculations ratio-nalize observations of sharpening of GB grooves with time during corrosion exposures, and show that vacancy diffusion quantitatively accounts for enhancement of IGC by reactive solute atoms, without in-voking solute segregation or precipitation at GBs. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available