Lewis is joined by a new student co-host, Frances Livera, to discuss how to find a solution we first need to properly define the problem with this month’s experts, Professor Iain Todd (professor of Metallurgy) and Dr David Bowden (UK Atomic Energy Authority).
Frances is a final year PhD student whose research is based around Additive Manufacturing and Brazing.
Iain is a Professor in Metallurgy at the University of Sheffield who has previously worked in Spain and the Netherlands.
David is the lead in Materials for Fusion at the UKAEA who has previously worked in both academia and industry.
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• The Henry Royce Institute (http://www.royce.ac.uk) ; the UK’s national institute for advanced materials research and innovation
• Royce at the University of Sheffield (http://www.sheffield.ac.uk/royce-institute)
• The University of Sheffield (http://www.sheffield.ac.uk)
• EPSRC and SFI Advanced Metallic Systems Centre for Doctoral Training (http://www.sheffield.ac.uk/metallicscdt)
• Department of Materials Science and Engineering (https://www.sheffield.ac.uk/materials)
• Modern AlChEME (https://sites.google.com/sheffield.ac.uk/modernalchemegroup) research group
Hello and welcome to materials unlocked the podcast where we take a look at the less known subject of Material Science and try to unlock its Mysteries my name is Dr Lis Owen and I’m a lecturer at the University of Sheffield in each episode with the help of some students friends and colleagues
We’re going to delve into a particular topic and hopefully unlock its potential so in this episode we’re going to be talking about defining the problem thinking about how we go about translating a problem that we might have into an industry into a challenge that we can tackle from a materials point of
View and as always uh on this journey I am joined by one of our current students in the department and this week it’s my great pleasure to introduce Francis Lia Francis welcome to the podcast hello thank you for having me you’re very welcome Francis do you want to tell us a
Bit about yourself you’re currently in your fourth year as a PhD yeah so I’m in my final six months of my PhD oh gosh where it really gets serious at this point yeah and my PhD focuses on brazing of additively manufactured materials essentially it boils down to the joining
Which is brazing using a metal that melts and then resolidifies of am components so additively manufactured and these are metals that you process using a laser to rapidly melt and resolidify them and we’re basically seeing how those components differ from stuff that’s been traditionally manufactured so you’re interested in
Actually if you create these these new joints whether that improves the property of the final component so you’re not necessarily designing the new materials you’re looking at the materials response sort of further down the line is that right exactly so I’m very much looking at the fundamentals of how something that’s been manufactured
In a different way impacts the future joining steps and with all the benefits of additive manufacturing how does that actually influence the next step of the entire material Journey yeah so for those who um additive manufacturing some people might not have come across before but it’s it’s uh a type of some people
Might know it more commonly as 3D printing um and have seen it with plastics and in fact we’ll have a whole episode later uh in the podcast series about this very topic but today we’re we’re talking about um as I say defining the problem and thinking about how we
Translate that Francis you’re if I remember correctly onor CDT is that right so you’re part of our Center of doctoral training here at the University and through this the this this Center of doctoral training often people work quite closely with industry do you have industrial collaborators on your project
Yes I do actually I’m sponsored by the UK aea oh right yeah handily we’ve got someone in the room who’s an expert in that field so yeah I work very closely with the special techniques groups at the UK atomic energy Authority and they primarily look at
Joining work as well so it fits really well with my PhD research yeah well this brings us very nicely onto our Specialists for today so uh we’re joined by uh two people uh one in the room and one remotely uh as Francis has said we are joined today by someone from the UK
Atomic energy Authority Dr Dave Bowden who is a group leader in Material Science at Uka so Dave uh welcome to the podcast thanks very much leis good to be you here so Dave uh could you just tell us a bit about your your background to
Begin with how did you end up at ukaa what where where did you come from were you a material scientist to begin with or have you taken a a different route to get here yes I I always sort of say I’ve taken a FY Meandering route through engineering
Um so I actually started off with studying aerospace engineering many years ago and since uh I I moved then into um ba systems where I actually worked um in the maritime Vision so sort of you know heavy engineering big Shipyard lots of you know really impressive construction going on and
Yeah really it was through that that I started to get very interested in nuclear propulsion and and everything that I’m was seeing being installed and it’s some of the submarines that I was um I was helping to build I actually then uh looked into some of the processing materials processing that was
Going into some of the components in those in those reactor modules applied for a PhD at the University of Manchester where I um I looked at some interesting wear resistant steals for uh pwr applications and that kind of LED quite nicely into me uh pursuing more in
The in the field of nuclear materials and and applied for the role at Uka where I’ve been for the last well nearly five years now been a very interesting journey I joined it just the right time it seems in terms of the kickoff of the um sperical toac elery um production
Program so um that’s the step program which is otherwise known as spent the first few years very closely involved in that um you know needing a lot of the efforts around material selection and definition so very interested by the topic you mentioned today because I’ve been sort of at the coold face with
These sorts of interesting challenges and definition requirements and that’s that’s kind of led to me where I am now spearheading development of new materials primarily structural Steels uh for fusion power plant applications in the future that’s fantastic yeah we we’ll pick up on a number of those
Things today as we talk about it I think in uh in our very first episode we talked about Material Science as a sort of very broad subject and how people get into Material Science and I think it’s not uncommon for people to come through various different Roots I came from sort
Of the other side of things coming from chemistry and possibly coming from the more fundamental theoretical side whereas it sounds like you’ve come much more from the applied side and always been interested in that sort of application and much more the engineering Focus um of Material Science
And Engineering because in fact here in Sheffield we are the department of Material Science and Engineering so we have that joint science and engineering Focus absolutely yeah I don’t think I’ve ever done any sort of aspect in isolation it’s always been yeah the science has always been towards an
Applied goal um which is yeah obviously really nice when you’re working on those subject areas to know that there is a application for the work that you’re doing um ultimately to deliver something in an engineering context so that’s been really rewarding yeah absolutely and I we always need to have that Concept in
The back of our minds as to how it affects the choices that we make when designing materials so that’s something we’ll pick up in more detail but just before we do I’m going to introduce our other speci specialist in the room Professor Ian Todd who is a professor
Here at the University in Sheffield a professor of metalogy and materials processing and is a fellow of the Royal Academy of engineering Ian welcome to the podcast oh thank you very much for inviting me along leis oh it’s an absolute pleasure so Ian a similar
Question to you to to to Dave could you tell us just a bit about your background your research what you do and possibly how you work with or give us a flavor in some of the the work you’ve done in the past particularly with that sort of
Industrial mindset yeah so I am a Metalist started off doing metalogy and I actually did my degree here a very very long time ago now and since then I mean the thing that’s always interested me about it is how do I make a material into a really complicated shape and how
Do I guarantee that it’s going to perform as I want it to and that’s the sort of question that’s always driven me uh throughout my career can I make this not just in the right shape but with the right performance straightaway so this idea of performance on demand and that’s
Where I got into additive Manufacturing in that way or 3D printing as you mentioned it’s often called 3D printing allows you to take that very complex shape which is really good fun to play with by the way you get some great ornaments to put in your office and beautiful little lizards absolutely
We’ve got more lizards than you could shake out we used to make genuinely used to make a lot of minions at one point to give away um but you know beyond that we’re also able to make very complicated components that sit in Rockets or sit in of you know things like Fusion reactors
And it’s very easy to do that in some respects you know can always make the form but the question has always been would you want to use it and so that’s where we’ve got into working across understanding what the process does understanding what the what’s going on when we’re making it understanding what
The properties are likely to be when we’ve made them and like I said that’s that’s the kind of thing that’s driven me throughout my career in a really nice way actually so I’ve worked with lots and lots of great students of course you mean people like Francis here for and
Over that time and it’s been interesting to see it go from being a real just a curiosity you know we were the the freak Show at the end of the the tours behold they are making parts from thin air uh to it being the point where everybody really understands what 3D
Printing is so that’s been an interesting Journey yeah because 3D printing as a sort of field has really taken off in the the last few years and you know lots of people have these little modules at home and things but I think one of the the interesting things
You’re talking about with this uh shaping of components as I said there’s a lot of misunderstanding about what material science is and I don’t think people necessarily appreciate that we’re designing things at all length scales right from you know thinking about what’s going on the atomic level to the
Microscopic level but also on that sort of macroscopic level of the shape of a component that you can hold in your hat and the materials properties contribute to that that challenge at at at every length scale absolutely and I mean you can look at it from both directions so I
Think material scientists tend to start off with you know what happens in in between atoms and then work upwards yeah that’s where I tend to sit think understand kind but as I start I start at the other end of it which is like this is the scale of something that I
Want to build and it can be you know on the scale of a jet engine component or it could be on the scale of sort of a Minion or whatever you want to make and then it’s what does the what is what has to be in the right order in order to
Give you the mechanical performance or the the the functional performance which is sort of magnetic or Thermo Electric or something like that that you actually need how do I do that and those two things don’t necessarily connect terribly well the bit in the middle the messy bit where you turn this beautiful
Thing that you made in the lab on you know tens of nanometers into something that’s a meter and a half in size and that’s really the fascinating thing about Material Science it expands that Lang scale let’s pick up on some of these uh indust sort of things and uh
Choices that we’ve we’ve already sort of referred to and actually where I want to start um I’m going to move move back to Dave to begin with because the UK atomic energy Authority is looking at how we might get nuclear fusion to work and nuclear fusion is one of those things I
Mean we’re sort of moving away from from materials now and a bit more into physics but uh nuclear fusion is one of those things that you often hear talked about in the news people are very interested about it and the potential that that it offers Dave I wondered if
You could kick us off by just helping us to understand just what nuclear fusion is like how it works and why it might be important for us and our our energy sector going forward absolutely nuclear fusion is obviously a process which is happening all around us and certainly
Providing um one of our primary energy sources on the earth which is our our sun and and we’re basically trying to replicate what what we can what we see from our our local star here on Earth but obviously bearing in mind some of the limitations
That we have compared to what the sun is doing so the sun is using immense gravity to basically fuse hydrogen Isotopes together to produce um immense amount of energy as a result and we don’t have you know the capability to use massive gravitational fields in that
Way on on Earth but what we’re we’re using instead of magnetic fields to confine superheated plasma and we will superheat two specific isotopes of hydrogen jerum and tritium and these are then confined within the in the magnetic field and we at Uka we’re pursuing a Taurus configuration so there are
Different types of fusion such as inertial confinement and and we’ve obviously heard quite a bit about that in recent years um particular with results from the US where they’ve actually achieved what we call break even in the in the fusion space whereby they’ve produced more energy out than
They’ve had to use um to actually start the reaction but as I say we’re focused on magnetic confinment fusion and and that’s developing this Taurus of donut shaped plasma and within that we have our duum and tritium and we heat that plasma up to somewhere around 150
Million degrees C and that enables uh the Isotopes to overcome the electrostatic repulsion that they otherwise would have so we basically ionizing and stripping the electrons away to allow those those Isotopes to fuse and then from there when that fusion occurs we produce a neutron and helium it’s really the neutrons that
We’re very interested in um from an energy perspective because those pass into our surrounding materials and interact with those materials and actually enable us to capture um the energy that they they possess so it’s actually a transfer transfer of the kinetic energy of the neutron into thermal energy as it’s implanted into
The surrounding structure and that we can capture and extract and use that to drive ancillary systems which would put energy on the grid so things like turbines for instance um which would be driven by the heated coolant that we will circulate through that that plant I should mention the helium does have a
Another important function because that also imparts thermal energy into our plasma which actually keeps the plasma nice and hot um so actually once you get to that point you’ve got what we call a plasma a burn basically so the the reaction is self- sustaining and that’s that’s always been you know something
That we’ve been pursuing in the field with Magnetic Fusion is getting to this point where we can have a stable consistent plasma um which which gives us a very steady stream of energy that we can then capture and and use um to put onto the grid so in a n nutshell
That’s uh that’s fusion and sort of how it works and and the reaction that play it’s um when we’re talking about the fuels and and you know the sort of equivalency it’s a very clean energy source so actually dyum one of the Isotopes that I mentioned is readily
Available in water so there’s a huge abundance for many um thousands of years um if we had a whole Fleet of fusion reactors running globally we wouldn’t be anywhere near to worrying about exhausting that supply for many melenia tritium on the other hand is a little
Bit more tricky um so tritium uh isn’t naturally occurring there’s a tiny amount um formed in the upper atos spere as a result of interaction with cosmic rays but it’s a very tiny amount that’s not economically viable to capture um so most of our tritium that we rely on
These days actually comes from fishing plants primarily and the C do reactors in Canada which use have an element of heavy water in their systems which actually then enable tritium to be to be breed in those in those systems um but again it’s a very small quantity and
Where we’re talking about fleets of commercial Fusion reactors in the future then actually the demands on tritium Supply are going to be quite large so that’s why we’re very key on developing what we call the breeder blanket systems and that’s an area where our materials
Research in my team are are focused as I say on the structural material side but it’s these bruda blankets that are the central the Lynch pin really for all of um all of the uh useful outcomes of of fusion power really because the blanket will contain all of the coolant systems
So that will be driving the extraction of all the thermal energy to be put onto the onto the grid as electrical energy and it also will contain lithium bearing compounds and that’s where it’s really important that those lithium bearing compounds interact with the neutrons being generated as part of the fusion
Reaction and that then actually triggers a secondary reaction whereby the lithium um transforms into tritium and some more helium a weird separate the two which feed the tritium back into to the plant to be used as fuel and the helium will be taken away potentially could be sold
As a secondary product because helium is actually quite quite a scarce commodity itself so really that we’ve got this nice sort of life cycle whereby the plant actually becomes self- sustaining by breeding its own fuel which then is fed back into that fuel cycle so hopefully that didn’t didn’t go too far
Into the weeds there but that sort of Paints the picture as the sort of fuel cycle and the reaction cycle in a in a fusion re yeah no no that’s great there there are a few things I think it would be just worth picking up on there because I
Think one of the things with Fusion is that a lot of people have heard of nuclear fusion uh for for quite a while and people don’t necessarily have an appreciation of the challenges and roadblocks that are being faced in its successful implementation and just to
Pick up on on some of the things that you mentioned you mentioned the method with which we uh contain it obviously as you say in the sun it’s done by gravitational but then other people are coming up with different ways you mentioned magnetic confinement you also mentioned inertial confinement could you
Just explain what what inertial confinement is effectively inertial confinement is the US approach has been using lasers so it’s basically you’ve got a fuel pet um which contains your um Isotopes again your derium and your tritium and in this case they’re using lasers many lasers and these are all
Pointed effectively at that fuel pellet which then when they’re all fired at once causes super heating of that pellet and ultimately the pellet collapses onto itself and that allows the fusion event to occur and that and then the energy is released and captured as a result so um
That that is another method of achieving that there are lots of different different ways of doing it yeah yeah yeah there’s some where you can just fire projectiles effectively so you can fire the fuel at other fuel pellets just crash things together very quickly exactly exactly so yeah there’s many
Different flavors of fusion but yeah magnetic confinement is the one that we’re we’re pursuing and then as you say there’s with with any process there’s a question about Fuel and how we get fuel and this sounds you know quite miraculous that essentially you can create the idea is to create something
That creates its own fuel that you can feed back into the system it’s a you know it’s it’s a wonderful idea it’s fantastic and then also I mean the the the big thing then you’re talking about with breeder blankets and where we start to think about more the materials
Challenge is I suppose just on a very simplistic and basic level essentially what you’re trying to do is create a a miniature Sun that has to be contained within something you’ve got to have some stuff uh to put around it in a previous episode when we were um talking about
The materials design cycle in general we were saying that we’ve been very lucky in a way that for many hundreds thousands of years we’ve always had just stuff lying around that we could make things from you know we had stones or metal that we extracted from ORS and
Things but with these real sort of high-end engineering challenges we’re now having to create bespoke materials to really tackle these harsh environments that are being created by this engineering challenge absolutely so so we’re we’re looking at Structural Materials but we are we are recognizing obviously that there are conventional Structural
Materials which are versatile um so in in our case we’re looking at Steel conventional Steels have some quite severe limitations for us in the fusion reactor so for instance radioactivity is one of them so an interesting point with um Fusion reactors is that actually because the neutron energies are so much
Higher than you get with a fishion plant that actually we need to be concerned with how active Structural Materials become there’s no spent fuel with a fusion reactor so you don’t have to worry about um radioactive Fuel and and storing that for tens of thousands of
Years afterwards as you do with a fish plant but we do have um Structural Materials which can become irradiated during that operation or do become irradiated and then then as a result can become radioactive so when people talk about um traditional nuclear power plants and fishing uh nuclear power
Often people think about you know decommissioning and people are aware that there’s a sort of a lifetime to the the power plants with with this then this higher energy then is it anticipated that some of the parts might be needed to be replaced sort of more frequently uh during during the process
Yeah absolutely so you know some of the materials that we we have to consider might be swapped out on a regular maintenance schedule so you know we sort of talk with blankets breeder blankets you know and this is from the European Community as well as a broader piece
Talking about sort of main schedules between every four to five years of a complete Swap and that’s just because the the materials get damaged and degrade um during their operation um and need to be taken away and processed and then new materials put in their place so
Um you know the sorts of damage as we’re talking about with Neutron interaction go into the Realms of hundreds of displacements per atom of damage um which effectively each displacement per atom is every time we move a atom out of its original latis position it’s just sort of like snooker balls hitting or
Something it’s sort of like snooker balls snooker balls exactly you know one displacement would be either moving one snooper ball from its original position once if we’re talking about 100 s then actually it’s moving that same snooper ball 100 times and in fact you’re doing that to every snooper ball on the table
So if you’d arranged them in a very specific way by the end of the rearrangement things are going to look pretty messy um compared to that starting point and we’ve got exactly the same situation with atom latis so we we then have to account for those effects and and those those have huge
Implications because materials that look great from a starting point you know if we take them as received and test them you get lovely material properties um you know excellent strength excellent toughness all the sorts of things we’re looking for actually what happens when we start to Neutron radiate those is
They change dramatically and in fact in some cases it’s not even like you’re looking at the same material anymore so um normally we see effects such as hardening with a radiation so the materials become very brle they no longer have um the same sort of elongation you you had in the original
As received state so they lose a lot of their plasticity so you don’t really have any ability for the material to deform before failure which is a huge concern for us and then you then you look at things like fracture toughness and that that tends to drop very
Dramatically as well as a result so you end up with a very embrittled quite a sort of you know concern from an engineering standpoint that that these properties change so dramatically um from the starting point and that’s something we we do are well we really grappling with um in in the fusion
Community because we don’t have a test reactor all the time to get us to those sorts of levels of damage that the commercial reactor would experience so we currently have a device physically to give us 14 me neutrons and the hundreds of displacements per atom of damage so
We have to do a lot of this through extrapolation and this involves modeling and understanding how those materials change throughout life and starting to extrapolate those properties out um it’s a much longer time scales than we’re able to experimentally access at the moment yes is often one of the
Challenges in in a whole host of Industries I think that we can’t necessarily always test things in the exact conditions we want and we need to create Fair tests and models and use the data that we have in order to sort of extrapolate out um you onto that longer
Time scale oh I wanted to just go back to something you were talking about um earlier you were saying that you could potentially pick up on existing materials and adapt those and thinking uh you mentioned Steels which are you know one of the most sort of common
Materials that that people find in the world around and I think it’s often the case that when we look at these challenges we often start with existing materials and seek to sort of adapt them as well as sort of in parallel looking at making brand new materials so I don’t
Know if I turn some of the other people in the room and in with the the processes that that you’ve been looking at is is it a mixture of the two or do you find that it’s it’s predominantly one or the other I mean the reality is
That once somebody invents or creates a material and it gets through all of the tests that are required in order to get it into service so if you you know think about things we make airplane engines out of or we make cars out of or we do
That kind of thing so a lot of testing goes on between look I have this super new material and yes you’re able to use that in implants or J engines or air frames or anything so there tends to be a sort of a if you come up with a new process a
New way of making something the the pressure is on you to make sure that you don’t have to go away and invent a new one but unfortunately processes and materials don’t behave like that and we often find ourselves having to make these sort of Fairly clever minor tweaks
To either the chemistry that we’ve got in how what elements there are inside of the material or um basically just fundamentally go back to the basics of how the material is is behaving when you do all of these horrible things like shoot lasers at it and remelt it or hit
It with a hammer or whatever you we got to go back and understand what its reaction is and then try and work out how we use that hammer more gently or how we use that laser more cleverly in order to hit the properties that people
Still want to get so it’s a bit of a it’s a bit of a two sides really I mean you can take the roots of every problem requires a new material that turns into a very expensive and long longterm program work up to 30 years in fact plus
If you’re not very careful um uh or you look at it and you say with in a series of constraints which is a very engineering approach you know you say I’m only allowed to vary my composition a little bit or I’m only allowed to uh
Do this sort of very minor thing to my material um can I actually find a way of creating a object from it that is suitable for the new application that we’re that we’re considering to be fair when you’re working with industry they would much prefer you to do the latter
Than the for but sometimes unfortunately we have to embark on these Explorations again yeah yeah uh and and Francis the materials that you’re working with are they existing materials are they new materials or a combination of the two so I’ve actually designed my PhD around existing materials when I begun my research I
Wanted something that I knew that I could print successfully and repeatably and so I primarily work with a type of stainless steel which is 316l and this is is a steel which is very widely used across various Industries and the braze Alloys which I used for that joining process are also
All commercially available the ones that are looking towards more nuclear applications are ones that are less likely to radiate in a negative way as we’ve heard so there’s some considerations that I’ve used there but primarily I have used materials which are readily available because they are understood yes rather than having an
Entire PhD of finding a new material and then going back to the original research question that I had and I think that’s really interesting what you’re saying with the sort of defining the research question and brings us sort of to to this topic that we’re talking about in
General because we have materials that might have been designed for a specific purpose as you see you’ve got this stainless steel which has been designed with something particular in mind and now we’re thinking about how we might apply it to a new situ ation a different situation with a different set of
Challenges um associated with it and we can either adapt that material or as I say design a completely new material so in terms then let’s have a think uh in terms of the the sort of challenges that we we’re we’re facing so Dave if I come
Back to you then let’s have a think about the uh particular challenges that we might face um in a nuclear fusion reactor and the sort of materials challenges that we might want to focus and how we go about translating those sort of big engineering problems that that we’ve been talking about into
Something with a materials Focus so if I’m trying to design one of these materials that you’ve talked about for a a fusion reactor I I don’t know if we’re talking about breedy blankets or Another Part what are the design criteria that we’re trying to sort of focus on and
Narrow our our mind down to as I say some of the biggest challenges we have are obviously around radiation damage that that’s a big one for us in the breeder blanket so as I say we could be looking at hundreds displacements per atom and that’s going to have a huge
Effect on material properties you couple that with mechanical loads if we’re talking through life you know we’ be talking four or five years of operation applied loads you know we sort of typically talk about applied loads in the blanket region of 100 megap pascals or so and then you start to look at
Things like the creep life of conventional materials such as steel that we’ve mentioned and and particularly we look at um reduced activation for atic Mantic steel so I mentioned we have this issue with radioactivity so we have to use Steels where we take out Elements which
Otherwise we would love to use in steel because they give them great properties but we need to substitute them with lower activation variants sorry you mentioned the radioactivity and the Damage you mentioned the strength of the material and you also mentioned the the creep Life Could you perhaps just
Explain what what creep life is it’s effectively an ongoing process in materials it’s accelerated by temperature and basically it’s any material that has a an applied load on it will deform gradually throughout overtime and as I say as the temperatures rise that that defamation will increase so it’s effectively like
Hanging a weight off of some blue Tac is sort of the analogy I use you know gradually that blue tack will start to stretch and the same thing happens in in materials that’s that’s creep basically but that has huge implications in a design space because it obviously modifies your geometry of the component
Eventually will start to lead to failure of that part rupture and plastic collapse because um the material will become so deformed so thinned in regions where it’s deforming that actually it can no longer tolerate the stresses in that region and will fail so that’s what
We refer to as a creep rupture life of a of a component and you know for some of the Steels we’re looking at such as ftic Mantic steals those creep lives are very low at high temperatures um so we we are often talking about trying to increase um the operational temperature of the
Blankets because with a higher operating temperature you get a much greater thermodynamic efficiency and and we often need that sort of margin in the reactors we’re talking about with that extra extra bit of temperature in some cases we’re talking about running 100 degrees hotter than the top end of
Current conventional Steels can handle so we’ be going from about 550 degrees C up to 650 degrees C and that can make all the difference in terms of the margins for the operation of the plant putting out enough net energy for it to be commercially viable it’s also a huge
Amount of obviously extra income um from anyone who’s operating that plant in terms of the revenue generated for the energy produced so that we’ve taken that as one of our key challenges that we have to be able to offer materials to run at these high temperatures to offer
A you know a favorable economic proposition with with the whole plant and then that brings in its its own new challenges and as I’ve alluded to the creep aspect is one of them and then creep damage can become exacerbated under a radiation so we get a swelling
Effect under a radiation as well and then this can contribute to a reduction in creep life in the material so what we’re doing is trying to engineer um conventional Steels taking the ftic maltic Steels we might might think about using so one example this is called Ura
97 it was developed back in the ’90s in by the European crowd had several Generations before then was originally generated from um grade 91 steel so that sort of taken as the base grade 91 isn’t reduced Activation so they had to swap out the elements and make it clean um
And basically we’re looking at modifying this urfer to include nanop precipitates in its Matrix to actually constrain Creek damage so to capture dislocations which otherwise would glide through the structure and allow this plastic deformation to occur we need tiny precipitates in that structure to capture that damage lock it in and
Prevent that creep from becoming excessive um so that’s where we’ve taken you know the sort of end point in terms of you we know we can scale Steels up to the level we need we know how to join them on the most part although there are some big challenges there still but we
Know we can manufacture tons of steel so what can we do at the beginning of that process to modify it to give us those those precipitates in that structure to actually address that that problem around the creep line Lifetime and that’s the sort of Route we’ve taken alluding to Ian’s earlier comment about
Sort of um looking at things from from the end and then going going back from there it’s the it’s the same thing it’s otherwise we could go right back to the drawing board and invent a new material um to do this and and and there is still
Working in that area but then you get the issue of how do you upscale that and translate that to to an industrial scale so we’re definitely looking at the sort of matter end of that process and then trying to reverse engineer it to get to
A point where we can we can develop mic structure that that attacks those challenges yeah so looking at it on those on all of those length scales as you saying coming from that that applied end and I think one of the the things to pick up on there is also the fact that
Often with these materials Challen we’ve got a whole Suite of design requirements that that we’ve got here you know we’ve got um uh as I say radiation damage uh strength we’ve talked about creep life uh temperature you talked about as an important factor uh in there as well and
Often you’re performing this sort of huge Balancing Act between these and sometimes the very thing that improves one of your properties will make one of your properties much worse I can see Ian smiling in the room and nodding and I’m sure this pain is is experienced across
A number of different sectors but it’s it’s the real sort of the the almost art of Material Science sort of balancing these different effects and and how we how how we do it but yeah so I mean so when you when you do do these things I mean you allude
That to you know that here we go we’ we’ve uh we’ve got Europe from 97 which kind of tells you how long ago we we we fixed that and now we’re wanting to put something else in it and um it’s like whack and mole right so uh or I use the
Analogy of the the old lady who swallowed a fly U what you’ve got to avoid when you’re doing all these processes and all these changes is swallowing the horse at the end um and we can add a small amount of this to to to modify something else and but then of
Course we have to spoil it all by making it into an object or we have to spoil it all by joining it together or we have to spoil it all by putting it into it into service one of the wonderful things that’s become a real tool for the
Material scientist and engineer I guess over the past at least 20 years as computational speeds have gone up is of course modeling and um whilst I’m not a model and I’m going to speak entirely from the position of ignorance you know the work that modelers do in terms of
Understanding the the processes that go on like the displacement and and understanding how you might actually do something to to reduce that a little bit uh the understanding of how they they model creep how they model the process themselves allows us to if you were going to do do a development program
Hopefully speed that up a bit so I said it was 30 years but hopefully you know if we use digital Technologies and we use these these new approaches uh we should be able to reduce that by you know a significant amount I’m not going to say what but a significant am and the
Nice thing is that of course if you understand that you’ve got a good mathematical or computational model of the material and you understand that it actually predicts things like performance and properties like uh how strong it is how what its creep rupture life is you can use that to help you
Also to design how you make it uh so understanding all of that becomes very assistive to people like me who go and you know spoil it all by trying to make a real object but there is incredibly helpful and and that combination of as as you alluded to Dave you know the sort
Of you’re wanting to understand what the properties are going to be like in 20 years well you could sit around and wait 20 years or we could use modeling to help us to predict what it’s going to be like in 20 years and if we’re happy and
Content that we’ve got models that are assisting us then actually that that modeling aspect is something that’s really speeding us up both in our understanding and also how we make it yeah I think that you know certainly stops you having to go into the lab and make thousands of sounds
Absolutely yeah so in Fant in the next episode we’ll be T talking to a couple of modelers uh about this in a in a little more depth and how we can use modeling to predict materials properties speed up make uh give us an understanding of the different uh
Materials that might form and all of those sorts of things but I think one of one of the the things to sort of draw out also of what what you said there is that it highlights how closely Material Science as a sort of academic discipline lies to Industry
And how there’s so much back and forth between the two uh even more so than subjects like chemistry or physics we have to work so closely with people in Industry to understand data that’s coming out of real life situations the choices that we’re making and as you
Said that feedback loop between the two um going going going round and round yeah so there’s a thing called technology Readiness level that gets used a lot by industry and that what what technology Readiness level says is have you just had this idea in the shower that okay that’s what they call
Trl1 right you you’ve had that idea and then we have this development scheme you know where you go up to a number it’s it’s it’s a number it was developed by NASA when they were looking at sort of whether space platforms Rockets where need to go but the higher what we call
Higher trls higher technology radi levels is when you’re actually looking to implement this in in an industrial environment and what happens is what you might have your design right you might have the design of your everything correct uh at that point often your materials start to do things that you
Don’t want them to do or they don’t perform as you want so you can often get the challenge of a what is classically sometimes called a science Problem by some of our industrial Partners popping up inside of a big engineering program and that’s where you’ve got to go back
And understand how you you know understand what the processes you know what the structure that you’re creating what the process is involved in putting your rocket nuclear reactor you know Fusion reactor together what’s happened during that and why is that performance now not as it should be and and you you
Sort of go in there and kind of try and fix it it’s it’s often requires a lot of thinking and a lot of nashing of teeth but it is usually usually fixable and it’s usually nonobvious how to do it so it’s a case of going back then to the
Engineering teams and saying okay avoid doing this bit y if we handle it in another way then will actually avoid that and we’ll get it through to service and that won’t show up again but sometimes unfortunately the material just won’t behave and that’s when that’s when a sort of a significant rethink uh
Can can turn up so unfortunately sometimes material scientists and Engineers are seen as Gatekeepers and the the stoppers of Wonderful projects uh but it’s actually fundamentally if we don’t get it right the safety of the whole program is a is at risk yeah absolutely and I believe uh I’m I’m
Right in saying Dave that um you know materials is one of the the roadblocks that has been both identified within the UK and more broadly by people in Europe working on Fusion as one of the key things that we need to understand for the successful implantation of
Fusion absolutely for years for years it was the plasma physics but I think you know there’s a sort of recognition that we we’re turning a corner at the moment with that and um you know there’s real confidence that that what we’ve demonstrated over the past few years at
Uka as well both with jet The Joint European Taurus and the mega sperical toac that we’ve got on site has really validated you know a lot of the plasma physics that’s been um hypothesized and put forward over the years um so we’re really feeling like we’ve turned that
Corner but yeah it’s it’s now looking at well actually how do we build this thing and how do we make sure it survives for the life of of the plant and and suddenly it’s the the materials are very much as you say one of the sort of
Limiting factors um so there is a very interesting road map as well I should mention that’s um available online where is the fusion materials road map um an exercise we carried out with Roy back in um 2021 that’s openly available for for people to read but that that did
Identify some of those key blockers from the materials perspective so what what some of the key challenges are and some of those already discussed today but also what materials could be developed to address some of those challenges and and what those development uh Pathways look like so yeah absolutely I think you
Know there is this recognition that that you know if we can’t if you don’t get the materials to work then you know we’re not going to get the plant to work it’s sort of that simple really or certainly the plant may not be as um as
Reliable as you would want it to be because components would have to be swapped out so regularly so that’s where yeah we’re sort of having you yeah we’re stepping in uh as material scientists and and stepping up our game in in that sense trying to offer some you know real
Solutions to these engineering problems um to actually make this thing a reality and that’s where you know this this exciting collaboration between industry and Academia comes in and where people like Francis you know get to get to work on these exciting problems for was it something that like coming to study a
PhD was a particular interest or Draw to you that sort of engineering focus and that sort of applied side of the problem yeah absolutely so I’m actually like you and I’ve got a master’s degree in chemistry there we are so we’ come from the best background the best background
But I knew that I wanted to look more at the fundamentals of stuff that is actually truly applicable in life and I thought I wasn’t getting that out of my chemistry background and so I wanted to look at something which had a really clear application and even going back four years ago the
Level of research in am was completely different Focus to what it is now and keeping up with that and knowing that I’m playing even if it is a small role but a role itself in making nuclear fusion a reality that’s really like the bread and butter for me yeah yeah it’s
So it’s so exciting to think that you know this might go into a real component real part that could that that could change the the way that we work on these things just picking up on on something else um that was mentioned earlier in you talked about these uh trls obviously
For someone like Uka I suppose that you’re working across sort of the whole the whole TRL range you’ve got a mixture of both sort of the very fundamental stuff going on and then also you know something that’s about to go into to to a real com component and then do you
Work with those things sort of across the range solely in-house or the there’s this collaboration with with Academia and sort of people like Francis or you know academics of various institutions I wondered if you could tell us a bit about that sort of side of things do
Yeah so yeah as Ian mentioned yeah trl’s resonate strongly we use them we use them a lot as a as a metric in houses to where we are with our different material development programs and as you say leis we’re working across the piece so um we
We sponsor a lot of PhD students and obviously France being being one of those um which is is great great to hear but yeah so so we’re looking at you know some of the lower TRL problems I would say often you know we’re discussing with Academia so not just through PhD
Projects but also collaboration where possible so for instance I’m I’m running a program at the moment focused on developing new Steels and neutron radiating them to to validate their performance in a in a fusion um environment uh we’ve got uh 10 different collaborators in that program including
A mix of both Academia and Industry and really what we find there is that we’ve got the very fundamental development aspects um sitting with Academia and and then obviously the analysis of those materials going through um academic Partners so using high-end techniques like transmission electron micros or atom probe tomography to really probe
And investigate these materials um that that we’re we’re producing and then um we’ve also got industry involved who are very much focusing on the intermediate to higher TRL levels so thinking actually how do we upscale this material how do we take what we’ve produced in the lab and actually replicate that at
Intermediate and larger scal so looking at things again like steels for instance it’s you know in the lab we’ve got very good control on cooling rates and and volumes of material so we can be really um really sort of specific um about how those materials are actually produced
And and what the end result looks like when you start to look at multi-ton ingots of the same type of Steel that you suddenly want to produce then your coing rates actually are meant um you know in some some cases we’re going from the lab where the calling rate can be
Measured in in minutes or perhaps even you know seconds in some cases when you’re talking about this with multi-ton ingots being produced you know with a big industrial um manufacturer then you could be talking about calling rates lasting days or weeks even so suddenly you’ve got very different um you know
Sort of material production and pipelines you also then start to worry about things like segregation you know and and how how you actually replicate those materials in the same way so we do really yeah have to address the entire piece and and really it’s trying to do
That in some ways all at once because we don’t have that luxury of time to sort of move from one progressively to the next because if we do that then again as ear is alluded to you’re probably looking at you know a solid 30-year sort of development time scale to get to that
Point where you can safely say you’re there at trl8 or nine ready to put it into into the component and operate it so we’re really having to sort of fill in the gaps um in par as much as possible and to really build up this this picture of how this material
Performs across the piece and we can’t do that with just industry or just Academia we absolutely have to have both involved at the same time in this process so as I say that’s one of the programs we’re running right now and it’s it’s working really well and it’s
It’s been eye opening I think for everyone looking at everything from a different perspective to what they normally would would sort of experience and I think for for me that’s one of the really exciting things about materials is people from different backgrounds with different Insight uh to to problems from a slightly different
Aspect each with their own expertise and slightly different focus and and understanding and bring that all together um to tackle these immensely complicated problems that as we’ve said have got you know a huge number of variables factors considerations that we me need to make in the design of an
Overall component that goes into a nuclear fusion reactor or a plane or whatever whatever the system is that we’re we’re trying to design for a particular purpose well that I I think that’s been a fantastic discussion so far just before we finish um are there any final comments Dave is there
Anything that that you’d like our listeners to particularly know about the work that you do or anything else that you particularly like to to say I will just say I think yeah at the moment it’s obviously an incredibly exciting time uh in the in the industry in the fusion
Sector I’d say anyone considering the nuclear space or or potentially considering a career in in nuclear material science it’s now is absolutely the time um I think you know something of a Renaissance at the moment I think it’s an incredibly exciting time a huge amount of challenges for material
Scientists to address in the coming years um but really critical challenges because you know obviously whilst the work we’re doing at Uka and and obviously a broader across um sort of renewable and sustainable energy generation sector is not only interesting from A Material Science and Engineering perspective it’s also
Incredibly crucial given you know what we’re seeing in the media at the moment around climate change you know and and these very dramatic changes in climate over the last few years even so it really sort of presses that message home in terms of we really need to come up
With some solutions to this problem and we don’t have the luxury of another sort of century or half a century to sort of worry about that and figure things out we need to get Solutions in place in the next next decade or two so that really
You know I think gives us a really good motivation it’s um you know it’s really nice and fulfilling to have that challenge and know that you’re you know contributing to something at that level and I think yeah it’s honestly it’s fantastic if we can inspire a few listeners who potentially are
Considering um careers in in that space to potentially come and chat to us or you know even drop an application and because yeah it would be fantastic to obviously have the next generation of Engineers ready to to pick up some of these challenges I think that’s a very
Very well put there are so many challenges across a broad range of problems not just in the as you say the environmental and energy sector but a a number of different engineering areas at the moment that require that material’s understanding which people have have suddenly realized over the last 10 20
Years that that’s really where we need to to push things because as you mentioned earlier sometimes even even small incremental changes can have huge effects when you’re working on those small margins raise being able to raise the temperature by 10 15 20° can can have a huge overall effect um on on what
You want to do and that all comes down to you know the ability to have those materials so yeah that’s fantastic Ian do you have any any further thoughts I I mean you know just to Echo really what what David said there I mean it’s you know materials are so energy intensive
In the way we make them uh but they’re so useful in the in the things that we can use them for I think we need to actually sort of look at world around us and kind of value it a little differently to the way we do it at the
Moment as I say we sort of take for granted that we have material absolutely and we take for granted that we can do things like just recycle our way out of problem so in fact actually that’s not necessarily going to be the case so understanding that we’ve got a
Limited resource it’s finite it uses a lot of energy to make it should we value materials a little bit more as a society and can we look at it a little little differently and make sure that we make better use of it and I think all of that
Comes together in the way that we’re encouraging I think our our new material scientists and Engineers to think about the world is to is to consider the resources that are being used in a different way and again like I say just value those in a different way to the
Way that we’ve done it in the past and and not using magic fairy dust to fix things you know not finding the rarest elements in the world and making a better material from it but using the stuff that’s more commonly available and uh that that is a big change that’s a
Huge change in mindset and it’s a very exciting one really and I what I like about interacting with our students coming in is that that’s now on their agenda very firmly and a lot of them are motivated to come and do Materials Science and Engineering because of that
So see how it unlocks that potential so but it’s it’s a really you know it’s a really different Viewpoint to the one that was there when I did my degree in the 14th century so it’s quite quite interesting that’s brilliant thank you and Francis any any final thoughts from
You I think I’d just like to Echo what both of you have said I think Material Science itself is becoming more and more of the central Focus even in the undergrad courses where I teach more and more the students are thinking about the sustainability about the long-term impacts of what they’re using how
They’re using it and so I think that’s really like the critical next step in Material Science and we’ll talk about this more in a in a future episode where we we’ll talk about the sort of the big picture and the grand challenges and things associated with for example Recycling and sustainability but thank
You all for for joining us on this episode so let me thank uh Dave Bowden for joining us remotely from Uka thank you Dave thanks very much pleasure to be you and thank you Ian for for joining us in in the room as well thank you no
Problem at all and Francis thank you very much for joining us thank you and finally to you our listeners thank you very much for tuning in and please do join us next time when our topic will be materials prediction thanks very much for listening if you want to join the
Conversation you can find us on Instagram @ materials unlocks if you want to find out more about the topics that we’ve covered and the work that we do a link can be found to our website in the show notes our thanks to the advanced metallic system CDT the Henry
Institute and the department of material science of the University of Sheffield see you next time