Hydrogen Embrittlement:
Hydrogen may be small, but it can rough up tough metals...
Hydrogen embrittlement knows no boundaries. No matter how it’s used and what was its source, hydrogen affects the properties of materials, creating many engineering challenges. The small and highly mobile hydrogen molecule can penetrate structural materials, break down ductility and other key properties and cause structural failure.
Chris San Marchi, a hydrogen and metallurgy researcher, is on a team studying how hydrogen and materials interact and how that affects the mechanical properties of materials. The research has important applications in energy, nuclear weapons and other areas.

“One reason Sandia has such a strong energy program is because of the institutional expertise developed to support gas transfer system (GTS) components of nuclear weapons,” he says. “Because of those decades of work, we are ideally situated to study the effects of gaseous hydrogen. This expertise helped the development of hydrogen energy programs supported by the president’s ‘all of the above’ energy strategy. We have what is probably the most comprehensive effort anywhere in the country studying
embrittlement from gaseous hydrogen, in particular high-pressure hydrogen.” San Marchi and colleague Brian Somerday develop codes and standards for hydrogen fueling stations and other energy-related uses of gaseous hydrogen in partnership with organizations such as the Society of Automotive Engineers, the Canadian Standards Association (CSA Group) and the American Society of Mechanical Engineers.

In the Hydrogen Effects in Materials Laboratory, materials immersed in high-pressure gaseous hydrogen, often at pressures more than 1,000 atmospheres, are put through fracture and fatigue tests. “We seek to validate and improve test methodologies as well as develop new ones for quantifying the adverse effects of hydrogen,” San Marchi says. The goal is to build robust codes and standards on a foundation of proven science while capturing all the insidious effects of hydrogen.

There is a need for global coordination of codes and standards driven mainly by the automotive industry. In the past year San Marchi has given seminars and discussed collaborations in Korea and France and spent two weeks at Japan’s National Institute of Advanced Industrial Science and Technology as a visiting researcher.
The energy program has invigorated Sandia’s hydrogen research in nuclear weapons. “Even with all of our experience, there is still a lot that is not well understood about uncertainty and margins for designing GTS components,” San Marchi says. “The tools we develop through energy research are allowing us to investigate materials more deeply. And in some cases, similar materials are used by both programs, which allows us to further leverage each area.” Better defined margins for GTS components could give engineers more design flexibility. For example, they might be able to reduce weight and volume, both of which are at a premium.

Last year San Marchi was on a team that investigated a hydrogen release at an AC Transit hydrogen fueling station in Emeryville, Calif. He and Aaron Harris, a Sandia engineer and program manager, worked with the state of California and others to investigate why the valve subcomponent failed. The construction material, type 440-C martensitic stainless steel, was a poor choice for hydrogen service, they concluded. “We were viewed as impartial experts in the field. This gave us credibility and clout to aid, in a small way, the reopening of the station,” San Marchi says. “We want to share our expertise on hydrogen with the community to help overcome roadblocks and setbacks to the deployment of hydrogen energy technologies.”
By Patty koning... *Note: There are some more articles regarding material sciences in the issue below that hopefully sparks further interest.

http://www.sandia.gov/research/_assets/documents/SandiaResearchVol1_Iss4_FNL.pdf

There are some more fascinating articles to be read and shared within the Sandia National Labs Research Magazine issues listed in the link below... So check them out and ENJOY!

Respectfully,
Henry

http://www.sandia.gov/news/publications/research_magazine/index.html