 My research question is try to understand what hydrogen, when it goes into a material, why it affects its properties so much. Hydrogen penetrating inside structural materials has been held responsible for catastrophes that you've all heard of, from the Fukushima accident to, for example, the old spillage in the Gulf of Mexico 10 years ago. We know it happens. We know hydrogen goes into materials and causes mayhem. It's been known for probably 200 years, but how it does it and how it affects the properties of the material so much is still a question that is begs for an answer. It's really difficult to go down to measuring individual atoms of hydrogen inside of a material because hydrogen is very light, it's very small, it moves a lot, very fast. There's hydrogen everywhere, it's the most abundant element in the universe. We really want to go down to measuring very small amounts of hydrogen inside of a piece of material, an alloy, a metallic alloy. When we think of metals, we often think of a big block, right? But this block is actually made of a lot of small bricks, a bit like you could think of LEGOs, for example. And every LEGO brick is of a different color that might reflect its local composition with, you know, for example, in a steel, some iron, some carbon, getting together and arranging themselves in a very specific way on a crystal lattice, as we say. And then the carbon sits around the iron in there and provides completely different properties locally to the material. And now we have this, you know, two friends of iron and carbon, and hydrogen comes in. What does it do? We don't know exactly where the hydrogen will be in the structure. What we know is that on a macro scale, it will tend to make the material much more brittle. When I start pulling on a piece of steel, after I've loaded it with hydrogen, it will break very quickly. We want to understand this, and we need to understand this. The approach that we are taking to do this is to find a way to freeze the material in the state where hydrogen is inside of the material so we can actually go down to precisely measuring where it is. What we have been developing here is built on an existing technology, but it is a way to take a piece of material and freeze it to about minus 200 degrees. What happens then is that the atoms won't be moving anymore. And out of this, we then shape a specimen specifically for a technique called atom probe tomography. So in atom probe tomography, what do we do? We have a specimen that is shaped as a very sharp needle, and we apply a high voltage to this of a few kilovolts. And what this does is basically pull the electrons down a little bit, exposing the atoms on the surface, and to an extent that the atoms can start to fly, one after the other, away from this specimen. And then we collect these atoms that have transitions into ions on a particle detector, and we measure the time it takes them to fly from the specimen to the detector. And why does it matter? It matters because a heavy atom will travel slowly, so it will take it a long time to reach the detector. However, a very light atom, like hydrogen, for example, will travel very quickly. So based on the time of flight, we can actually determine which is the elements that was sitting at that specific position on the specimen. So we collect these atoms, one after the other, after the other, a bit like we are peeling an onion, and we collect all of this data, and then we use a very powerful computer to reconstruct every atom at its original position. So I'll be able to see if I get back to my example of a piece of steel, whether I have a region locally that has, for example, more carbon or more iron, and I can position these hydrogen atoms inside of this volume. These insights will help me understand how a hydrogen behaves inside of the material. The first key finding is that by trialing several routes between getting a material and making a specimen and analyzing it, we could actually find the best way to freeze the hydrogen in position and then find the right conditions to get the optimal measurements in terms of precision of the amount of hydrogen that we can detect. This has taken a significant amount of time, but we could finally prove that we could do it. So we can go down to measuring individual atoms of hydrogen inside of the material. From a material standpoint, the material we had selected is very resistant to hydrogen embracement, and we wanted to know precisely where the hydrogen was sitting inside of this structure. Again, I was saying you have this hierarchy of different sections with atoms arranged in one way and another way, with, for example, carbon rich regions and iron rich regions. And so one of the key findings that we had was that hydrogen tends to sit inside of these carbon rich regions and also sometimes at the interface between the matrix full of iron and these carbon rich regions, these carbides that typically strengthen the material. So you could ask, why is it important that we could detect this hydrogen and measure it and quantitatively go down to measuring individual atoms like this? And it is relevant because, ultimately, the problem of hydrogen inside of these materials is when it's free to roam around. And if it is, then it might actually interfere with the way the material deforms and accelerate it. So accelerating the failure of these materials. But what we've shown is that by putting some of these particles inside of the steel, these particles can trap the hydrogen, locating it in a specific phase, preventing it from going around and causing mayhem. So we need to now take these findings and we can move backwards one step and say, okay, how can we introduce some more of these particles inside of the material initially to make it more resistant against the embrittlements that is associated to the presence of hydrogen. We have now a number of different projects that exploit some of the knowledge that we've gained from this primary work and try to use this to make steels that are better and stronger against hydrogen embrittlements. But not only are they better against hydrogen embrittlement, we also want to make them usable. So we want to not, you know, introduce elements that cost a lot of money because then it means that the impact of these new alloys will be probably minimal because the industry will never adopt them. We want to be able to use elements that are traditionally used in the industry so we can actually make materials that are relatively cheap, yet that actually will be very good against hydrogen embrittlement. Also, hydrogen embrittlement doesn't only affect steel, it also affects titanium alloys, for example, that go into planes. It affects nickel alloys that are used to drill holes to look for oil and gas, for example, which would still not be perfect. But also when we think about, for example, fuel cells and water splitting for the hydrogen economy in the future, hydrogen will also go inside of these small particles of metal that are used to break the water molecule into oxygen and hydrogen. We still need to understand what hydrogen does in these systems. So what we have now is a platform, a technique, that we can actually deploy onto a range of different materials to understand how hydrogen affects these materials more specifically. And this is what we're going to do through my group and all the groups within the Institute in the foreseeable future.