Steel is one of the strongest alloyed metals in the world. Which is why it’s used to construct city infrastructures such as buildings, roads, railways and bridges, and built into concrete structures to provide extra reinforcement. But this alloy isn’t completely infallible.
Steel’s weak factor: Hydrogen Embrittlement.
One of the main reasons steel is so strong is because it has various elements added to it, to increase its tensile strength. Some of these include nickel, manganese, chromium and vanadium. An element that doesn’t mix so well, however, is hydrogen.
If steel is accidentally exposed to hydrogen during the manufacturing process, there is a problem. Hydrogen diffuses quickly within the alloy, creating pressure to the point where it forms individual atoms. This process, called ‘hydrogen embrittlement’, weakens steel and leads to cracks – which causes massive issues for major engineering or building projects.
One such issue occurred in 2013 with bolts in the eastern span of the San Francisco-Oakland bridge failing tests. Weakened steel is not something you want on a busy bridge!
A new generation of steel and metal alloys.
A team of international researchers, including a University of Queensland scientist alongside scientists from the Oxford and Sheffield universities in the UK and ETH Zurich in Switzerland, have started looking at developing a new generation of steel and metal alloys to combat this weakness.
Professor Roger Wepf, Director of the UQ Centre for Microscopy and Microanalysis, says the researchers have, for the first time, localised and visualised hydrogen in steel. This, he says, is the first step in developing next-gen steel alloys with an even greater strength and endurance. The technologies involved included cryo-electron microscopy freezing, low-temperature sample preparation in a cryo-focused ion beam microscope, and inert cryo-transfer.
Hopefully with this new research, the chances of steel having weak points or cracking will be considerably lessened, making it much safer to use in the construction of city infrastructures.