Resisting Degradation from the Environment: A Symposium Honoring Carolyn M. Hansson’s Research and Pioneering Experiences as a Woman in STEM: Talks to Introduce Posters II
Sponsored by: TMS: Corrosion and Environmental Effects Committee, TMS: Steels Committee
Program Organizers: Jenifer Locke, Ohio State University; Brendy Rincon Troconis, University of Texas at San Antonio; Ashley Paz y Puente, University of Cincinnati; George Gray, Los Alamos National Laboratory; Suveen Mathaudhu, Colorado School of Mines; David Shifler, Office of Naval Research
Monday 2:00 PM
October 10, 2022
Room: 404
Location: David L. Lawrence Convention Center
Funding support provided by: Office of Naval Research
Session Chair: Jenifer Locke, Ohio State University
2:00 PM
Liquid Metal Embrittlement: Cracking Open the Disparate Mechanisms: Justin Norkett1; Victoria Miller1; 1University of Florida
Liquid metal embrittlement (LME) has been studied for over 100 years, but there is still relatively little generalizable LME theory. Recently it was proposed that explicit consideration of multiple mechanisms of LME can accelerate the development of broad multi-system understanding and enable the a priori prediction of LME behavior. This poster and accompanying discussion will review the status of LME research in the context of multiple separable mechanisms, explore future directions, and celebrate Dr. Carolyn Hansson's contributions to the field.
2:20 PM
Relating Microstructure to Environmental Degradation in Al-Mg Alloys: Josh Kacher1; 1Georgia Institute of Technology
Al-Mg alloys are seeing increasing application in naval and automotive industries due to their high strength-to-weight ratio and excellent corrosion resistance. However, these alloys are susceptible to sensitization at elevated temperatures, resulting in localized corrosion and stress corrosion cracking at the grain boundaries. In this study, we combine electron backscatter diffraction (EBSD) with corrosion and stress corrosion cracking experiments to relate microstructural characteristics to susceptibility to localized attack. This approach facilitates the rapid exploration of thousands of grain boundaries. In addition to the grain boundary and crystallographic orientation information, EBSD also provides insight into the local density of geometrically necessary dislocations. Our results show that localized accumulation of dislocations at grain boundaries promotes Mg-rich β-phase formation, increasing the susceptibility to stress corrosion cracking. We show that even low angle grain boundaries, which are traditionally considered resistant to sensitization, can form β-phase in the presence of local dislocation accumulation.
2:40 PM
Quantifying the Environmentally Assisted Cracking Initiation and Short Crack Behavior in New Generation 7xxx Aluminium: Tim Burnett1; Ryan Euesden1; Yasser Aboura1; Al Garner1; Thomas Jailnin1; Zak Barrett2; Christian Engel2; Phil Prangnell1; 1University of Manchester; 2Airbus
New generation (new-gen) 7xxx aluminium alloys offer benefits in improved toughness and corrosion resistance. However, they can be more susceptible to Environmentally Assisted Cracking (EAC) in humid air. Initiation of EAC cracks has several mechanistically distinct stages of incubation, development of pre-cursors, proto-crack formation and short crack growth. Understanding initiation whilst critical to the overall material performance has always been difficult to study due to its stochastic nature. In this work, a high-resolution optical scanning system was developed, capable of in-situ monitoring the surface of constant displacement (4-point bend) tests. This has allowed for the unambiguous detection of EAC initiation sites and the ability to monitor the growth behaviour of short cracks in relation to the local microstructure. Subsequent site-specific fractography, combined with high–resolution SEM-EDX, has revealed the nature of the preferred initiation sites. This has led us to re-define the meaning of KEAC threshold in these materials.
3:00 PM
Correlating Crack Tip pH to Environment Assisted Cracking Performance in Al Alloys: Jenifer Locke1; Katrina Catledge1; Gabby Montiel1; Gabriella Marino1; 1Ohio State University
Environment assisted cracking is driven by both mechanical and environmental driving forces for cracking that exist at a crack tip. The environmental driving forces at the crack tip, while related to the external environment, are predicted to deviate greatly from those that exist in the bulk environment. The literature contains modeling studies that predict the deviations of crack tip pH and potential from the bulk environment, but only limited experimental information exists. The discussed research spans several Al alloy systems loading in both corrosion fatigue and stress corrosion cracking scenarios to understand how and if performance changes are linked to changes in crack tip pH. For example, in sensitized 5xxx Al alloys large cathodic polarizations under low frequency corrosion fatigue led to crack arrest, which was linked to the development of a basic crack environment likely due to increased cathodic reaction kinetics in the crack wake.
3:20 PM Break
3:40 PM Cancelled
The Multi-dimensional Impact of Corrosion on Sustainability: Christopher Taylor1; 1Dnv Gl
Sustainability is an increasingly significant driver of institutional management transformation and prioritization. It impacts product design, is giving rise to new service industries, influences building architecture, industrial operations and maintenance, and often focuses on waste management and reduction. Since corrosion management focuses on enhancing the useful life of assets, as well as mitigating the risk of accidents that can have substantial impacts on human welfare and environmental quality, we argue that an organization's sustainability plan should also address its corrosion management practices. In this presentation, the author will survey the ways in which corrosion management is critical to: (a) preservation of societal investments in critical infrastructure, (b) enabling various facets of a decarbonized energy system, and (c) ensuring the integrity of the circular economy. Particular opportunities in which current and future research can be used to enhance the sustainability impact of anti-corrosion technologies will also be highlighted.