Tue, 25 January, 2022
The Corrosion Journal has published two research articles related to work led by TWI Materials Performance and Characterisation Section Manager, Kasra Sotoudeh, alongside former NSIRC student Lisa Blanchard and a number co-workers from UK and overseas research institutes and organisations.
The work discusses hydrogen transport and embrittlement on duplex stainless steels along with the associated challenges of quantifying these phenomena in relation to the effects of microstructure, stress risers, and the suitability of test methodologies commonly used to evaluate resistance to cracking in engineering alloys.
The first paper is related to a larger programme of research to study the resistance of a wrought and a hot isostatically-pressed (HIP) UNS S31803 duplex stainless steel (DSS) to hydrogen-induced stress cracking (HISC). The paper investigated material properties including the three-dimensional (3D) microstructure, distribution and morphology/geometry of the ferrite and austenite phases and their significance on hydrogen transport. These properties were determined quantitatively using X-ray computed tomography (CT), microstructural data analysis and modelling to provide a foundation to compare resistance to HISC initiation and propagation.
The second paper follows on from the first to focus on the role of stress and strain in HISC of DSS. The work detailed in this paper used experimental hydrogen permeation measurements and environmental fracture toughness testing (i.e. J R-curve testing) using both conventional and non-standard single-edge notched bend test specimens, to study significance of the severity of stress raisers. This study allowed interpretation of hydrogen permeation and transport test data as well as an evaluation of the suitability of environmental fracture toughness test methods for the assessment of resistance to HISC in DSSs.
Figure 1. Quantitative evaluation of resistance to HISC of a wrought and a HIP UNS S31803 duplex stainless steel
You can see the two papers, from the links, below:
- Paper One: ‘A Quantified Study of the Resistance of Duplex Stainless Steels to HISC: Part 1 - Significance of the three-dimensional phase distributions and morphological properties on hydrogen transport’ - Lisa Blanchard; Kasra Sotoudeh; Hiroyuki Toda; Kyosuke Hirayama; Hongbiao Dong (https://doi.org/10.5006/3960)
- Paper Two: ‘A Quantified Study of the Resistance of Duplex Stainless Steels to HISC: Part 2 - Significance of the hydrogen permeation properties and severity of stress raisers, on hydrogen transport and cracking’ - Lisa Blanchard; Kasra Sotoudeh; James Hesketh; Gareth Hinds; Hongbiao Dong (https://doi.org/10.5006/3961)
This work was partially funded by a TWI Exploratory project alongside funding from the Engineering and Physical Sciences Research Council, Centre for Doctoral Training (EPSRC, CDT Grant No: EP/L016206/1, 2016) in Innovative Metal Processing, and the School of Engineering at University of Leicester