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00:00:00
- This is one of the most
powerful jet engines in the world,00:00:03
and it actually runs00:00:04
at temperatures 250 degrees Celsius hotter00:00:07
than the melting point of the
materials that make it up.00:00:09
- [Assistant] That's 1,200 degrees.00:00:11
- So the question is,
why doesn't a jet engine00:00:14
just melt into a puddle?
(intense music)00:00:16
(jet hovering) - We are right at the boundaries
of the laws of physics00:00:21
(intense music) - That is wild.00:00:22
It's at the same temperature
now as it would be inside00:00:25
the jet engine.00:00:26
But here, they're liquid.
(dramatic music)00:00:28
- Every time I get on a plane,00:00:29
I'm thinking, "This is never gonna work."00:00:31
- And yet, it does work.00:00:33
Right now, there are over
10,000 planes in the sky powered00:00:37
by engines just like these.00:00:39
Maybe you are on one right now.00:00:41
So, how do they work?00:00:45
(energetic music)
(jet humming) This is a jet engine,
specifically a turbofan engine.00:00:49
At the front is this giant fan.00:00:51
During takeoff, these
rotating blades push 1.3 tons00:00:55
of air backwards every second,00:00:57
and around 10% of that
air gets compressed.00:01:00
The compressors force the air00:01:02
into increasingly narrow chambers.00:01:04
They compress the air00:01:05
to about 50 times atmospheric pressure.00:01:08
And just by doing that, the air heats up00:01:10
to around 600 degrees Celsius.00:01:13
This compressed air is then forced00:01:15
into the combustion chamber,00:01:16
where fuel is sprayed in
through a ring of nozzles00:01:19
and ignited.
(flames blasting)00:01:21
That chemical reaction
gives off a lot of heat.00:01:24
So the temperature jumps to
around 1,500 degrees Celsius.00:01:28
So now you've got this
high-pressure gas from the combustor00:01:30
that just wants to expand,00:01:32
and now it's got an incredible
amount of thermal energy.00:01:36
But between the combustion chamber00:01:37
and the outside air is this.
(intense music)00:01:40
Rows of turbine blades.
(blades humming)00:01:42
So, in order for the gas
to expand and get out,00:01:44
it needs to push these
turbine blades out of the way.00:01:47
And in pushing the blades, that is00:01:49
how it transfers its energy to the engine.00:01:52
This is where all the
power really comes from00:01:55
in modern jets on takeoff,00:01:57
each high-pressure turbine blade
is generating as much power00:02:00
as a Formula 1 car.
(car droning)00:02:02
And there are 68 of them.00:02:04
(lively music) As the gas rushes through
the turbine and nozzle,00:02:07
its pressure drops from around
50 atmospheres down to one,00:02:09
and it expands by almost 20 times.00:02:12
And that spins these turbine blades up00:02:14
to 12,500 revolutions per minute.00:02:18
The fan that is pushing
all that air backward00:02:20
and all those compressors
that squeeze the air down,00:02:22
all of that is powered by
the turbines back here.00:02:26
It's a kind of funny,
really counterintuitive way00:02:29
to think about an engine.00:02:30
It's what's happening in the back00:02:32
that's actually driving
everything up front.00:02:35
(pensive music) As the hot exhaust gas is shot
out the back of the engine,00:02:39
it pushes the engine forward.00:02:41
That generates thrust.00:02:43
But did you know that in
a modern passenger jet,00:02:45
this accounts for less than
20% the thrust of the engine?00:02:49
The vast majority of the thrust,
over 80% of it, just comes00:02:52
from that big fan at the front of the jet.00:02:55
(numbers beeping)00:02:56
Remember how only 10% of the
incoming air gets compressed?00:02:59
The other 90% bypasses all that.00:03:02
It's simply propelled
backwards by the fan.00:03:04
It goes right around
the guts of the engine00:03:06
and comes straight out the back.00:03:08
The fan pushes that air backwards,00:03:10
so the air pushes the fan forwards.00:03:13
That's how you get 80% of the thrust.00:03:15
It's basically a huge ducted propeller.00:03:18
(jet hovering) So, why do it this way?00:03:20
I mean, why not compress
all the incoming air00:03:23
and put it all through the
combustion chamber and turbines?00:03:27
(flames blasting) Well, some fighter jets do exactly this,00:03:30
and it makes for very powerful engines,00:03:32
but they're also horribly inefficient.00:03:35
To see why, remember
that the impulse pushing00:03:37
the plane forward is equal to the change00:03:39
in the momentum of the air backwards.00:03:42
So you've got options.00:03:43
For example, you could push twice00:03:45
as much air back half as fast,00:03:47
or you could push half as
much air back twice as fast.00:03:51
Both will generate the exact same impulse,00:03:53
but the kinetic energy of
the air is proportional00:03:56
to v squared.00:03:58
So it takes four times as much energy00:04:00
to speed up the air in the second case,00:04:02
and a lot of that energy is
just wasted in the exhaust.00:04:05
So, ideally, you want to
push as much air backwards00:04:08
as possible with only a
small change in velocity.00:04:13
(enchanted music) That's why jets have gotten bigger00:04:14
and bigger over the years,00:04:16
and the increasing fraction00:04:18
of bypass air has the added benefit00:04:20
that it surrounds the hot exhaust gases,00:04:23
and that reduces noise
coming away from the jet.00:04:26
But there is another
major factor when it comes00:04:28
to engine efficiency,
and that is temperature.00:04:31
At cruising altitudes around 35,000 feet,00:04:34
the outside air is around
negative 55 degrees Celsius,00:04:38
while inside the engine, it's
over 1,500 degrees Celsius.00:04:42
The hot, high-pressure gas
inside the engine wants00:04:44
to expand into the much colder,
lower-pressure air outside.00:04:49
It's that difference that
lets the engine turn heat00:04:51
into useful work.
(ominous music)00:04:53
But there's a fundamental limit00:04:54
to how much work any heat
engine can get from that.00:04:57
It's called the Carnot efficiency.00:04:59
It's equal to one minus the temperature00:05:01
of the cold outside air
divided by the temperature00:05:04
of the hot gas inside
the combustion chamber.00:05:07
(ominous music) So, looking at this, you
can improve the efficiency00:05:10
of the engine in two ways,00:05:12
either fly where the air is colder00:05:14
or raise the temperature
in the combustion chamber.00:05:17
One problem with that, though,
is that it turned the inside00:05:20
of a jet engine into one00:05:22
of the harshest environments
we have ever built00:05:25
in which machinery has to survive.00:05:28
- To keep a turbine blade whole00:05:30
and unaffected within an engine
is like putting an ice cube00:05:32
inside your oven, turning
up to max, leaving for work,00:05:35
coming back after an eight-hour shift,00:05:36
and finding it's still
completely frozen in the oven.00:05:38
That's what we've got to try
and do within that engine.00:05:40
- It sounds absurd.00:05:42
(intense music) Not only do the turbine blades sit00:05:44
in a stream of gas that's
over 1,500 degrees Celsius,00:05:47
they're also spinning at 12,500 RPM00:05:51
with the tip of each blade slicing00:05:53
through the air at nearly
1,900 kilometers per hour.00:05:57
Now, every blade wants to fly straight,00:05:59
but it's forced to spin in a circle,00:06:02
which means, something has00:06:03
to be constantly pulling it inwards.00:06:05
That's the centripetal force.00:06:07
If you take a representative 300 gram00:06:09
high-pressure turbine blade
and run it at that speed00:06:12
and radius, it has to be pulled
inwards with a force equal00:06:15
to the weight of 20 metric tons.00:06:17
That's roughly the weight00:06:18
of two London double-decker
buses tugging on each blade00:06:22
as it spins, all while
they're glowing hot.00:06:26
(ominous music) To make matters worse, at these
temperatures, oxygen wants00:06:29
to react with the metal
of the blades itself.00:06:32
And on top of all that, the air rushing00:06:34
through the engine often
carries dust, sand,00:06:37
and pollutants that can damage00:06:38
and erode the surfaces inside.00:06:41
And somehow, these blades have
to survive this punishment00:06:44
for tens of thousands00:06:46
of flight hours without
deforming, cracking, or failing.00:06:50
They really determine how
efficient you can make the engine00:06:53
because you can't make the engine so hot00:06:55
that the blades can't
withstand that temperature.00:06:58
So they determine the maximum temperature00:07:00
of the combustion chamber,00:07:01
and therefore, the maximum
efficiency you can realize00:07:04
with a jet engine.00:07:06
So what kind00:07:07
of metal could possibly
survive these conditions?00:07:10
Well, we sent Veritasium producer, Emilia,00:07:13
to the Department of Materials
Science & Metallurgical00:07:15
at Cambridge University00:07:16
to put some different metals to the test.00:07:19
(ominous music) - So this is the steel?00:07:20
This is the steel sample, yes.00:07:21
- Okay.
- So we've got00:07:22
about 200 megapascals to start with,00:07:24
which is sort of comparable
to some of the stress00:07:27
that's seen by these components
in real applications.00:07:30
And we're gonna put that stress on,00:07:32
and then slowly increase the temperature.00:07:34
- [Derek] This is a mild steel.00:07:36
It's relatively strong and easy
to form into complex shapes.00:07:39
It seems like a pretty good
bet for a turbine blade.00:07:41
And at first, under this load00:07:43
and at these low temperatures,
it holds up pretty well.00:07:46
We're essentially tugging on
all the atoms within the metal.00:07:49
We're not breaking or forming any bonds.00:07:52
We're just making them flex a little.00:07:53
And that slightly changes the
spacing between the atoms.00:07:56
And as a result, the metal
gets slightly longer.00:07:59
This resulting change in size,00:08:01
specifically the per-unit
change in length,00:08:03
is what we call strain.00:08:05
Critically, at this stage,00:08:06
the material is behaving elastically.00:08:08
If we remove the load right now,00:08:10
the material just snaps
back to its original size.00:08:14
In an engine, some elastic
deformation like this will occur.00:08:17
It can't be too big or
it'll cause problems.00:08:20
But what we really don't
want is plastic deformation00:08:23
if the shape changes permanently.00:08:26
And that's exactly what starts to happen00:08:28
as we keep increasing the temperature.00:08:30
- [Howard] It's getting hot now.00:08:31
That's a little bit of oxide.00:08:35
(ominous music) There you go, see this starting to deform?00:08:38
- [Derek] Now, bonds are breaking00:08:40
and reforming as the metal
at us deforms permanently.00:08:45
(ominous music)00:08:46
But this doesn't happen all at once.00:08:48
So I got the mechanical
engineer on our team,00:08:50
Henry, to build this demo.00:08:53
(ominous music) - Okay, so you can see
we're getting a bunch00:08:55
of tiny little bubbles,
and just naturally,00:08:57
they're packing into this
hexagonal arrangement.00:09:00
And there are actually a lot of materials00:09:01
that have atomic
structures just like this.00:09:03
But you can see it's not perfect.00:09:05
Like, right here,00:09:06
you can see there's an
extra half-plane of atoms.00:09:09
Well, in this case, bubbles,00:09:11
this is called an edge dislocation.00:09:16
(ominous music)00:09:17
It becomes really interesting when I try00:09:19
to pull this raft apart.00:09:21
(ominous music)00:09:22
You can see these little dark
lines that zip back and forth.00:09:25
Those are dislocations, and
they move through the lattice.00:09:28
As the dislocation moves, it'll
cause one plane, a bubbles,00:09:32
to sheer past the other one,
which shifts the structure00:09:34
by exactly one spacing.00:09:36
But there isn't just one dislocation.00:09:39
There are plenty of them.00:09:40
And altogether, their movement
produces dramatic changes00:09:42
in the overall shape.00:09:45
(ominous music) - [Derek] That's exactly
what's happening here.00:09:47
Everywhere that stress is high enough,00:09:49
billions of dislocations
are moving and interacting.00:09:52
The steel starts to deform continuously00:09:54
under this constant load
in a process called creep.00:09:57
It takes energy to break the atomic bonds00:10:00
as the dislocation travels
through the lattice.00:10:02
So, as we ramp up the temperature00:10:03
and all the atoms get more thermal energy,00:10:06
it no longer requires as much
stress to break these bonds,00:10:09
becomes much easier for
the dislocations to move.00:10:12
The metal effectively gets softer.00:10:14
Now the steel strength drops so much00:10:17
that the slow, time-dependent
creep gives way00:10:19
to rapid deformation.00:10:21
As it stretches, it rapidly
decreases in cross-section,00:10:25
and eventually, the remaining
metal can no longer bear00:10:27
the load.
(ominous music)00:10:30
Now, you could try doing similar tests00:10:32
for other metals like this titanium alloy.00:10:36
(ominous music) Titanium is about half as dense as steel.00:10:38
- Should feel that's quite a bit lighter.00:10:39
- Yeah, it's like loads lighter.00:10:41
- [Derek] So if we were
to make turbine blades out00:10:43
of titanium, each blade
would be much lighter,00:10:45
and that would reduce00:10:46
the enormous centripetal
forces it would experience.00:10:49
So it seems like a great choice.00:10:51
And at first, it performs really well.00:10:53
- That's 100 degrees.00:10:54
It's hanging in there.00:10:56
- [Derek] But as we push
the temperature higher...00:10:58
- [Howard] Oh, I can see some glowing.00:11:01
(energetic music) Oh, look at this, oh, it's gone already.00:11:04
(Emilia laughs) - [Derek] Just like the steel,
its strength drops rapidly00:11:07
as temperature increases.00:11:08
And that's true for most metals.00:11:12
(lively music) Yet, the first jet engine,
dating back all the way00:11:14
to 1941, actually did
use steel turbine blades.00:11:18
It was designed by British pilot
and engineer Frank Whittle.00:11:21
His engine powered the first flight00:11:23
of a British jet aircraft,
the Gloster E.28/39 prototype.00:11:27
When a colleague excitedly told Whittle,00:11:29
"Frank, it flies," he dryly
quipped, "That was bloody well00:11:33
what it was designed to do, wasn't it?"00:11:36
(film whirs)
(lively music) But Whittle's prototype
had two major flaws.00:11:38
The first was that the gas00:11:40
inside the engine, only
reached temperatures00:11:42
of around 780 degrees
Celsius, which was one00:11:45
of the reasons it was inefficient.00:11:47
And the second was that
it was only allowed00:11:50
to fly for up to 10 hours.00:11:52
Any longer, and it was too likely parts00:11:54
inside the engine would fail.00:11:55
And both of these
drawbacks were largely due00:11:57
to the steel turbine blades.00:11:59
Something that occurred to me is,00:12:01
why aren't they made out of tungsten?00:12:03
I mean, because tungsten doesn't melt00:12:06
until 3,400 degrees Celsius,00:12:08
which is more than twice the temperature00:12:10
inside a modern jet engine.00:12:12
But tungsten is also incredibly dense.00:12:14
It's about two and a half
times denser than steel,00:12:17
and it's also brittle, which
makes it hard to manufacture.00:12:21
And using a material00:12:22
that heavy wouldn't just
make the blade a problem.00:12:25
The components that hold the
blade in the engine would00:12:28
also have to carry much higher loads,00:12:30
well beyond what current
materials can handle.00:12:33
So, you can optimize for one
thing, like the melting point,00:12:36
or a different thing
like strength or weight.00:12:39
But the turbine pushes
every variable to its limit.00:12:43
So what are these blades00:12:45
actually made of?
(energetic music)00:12:47
Well, to find out, we went00:12:48
to Rolls-Royce's precision
Casting Facility in Derby,00:12:52
and it turns out the world's00:12:53
most advanced metal parts
begin life as, well,00:12:57
something surprising.00:12:59
(lively music) What is with the, like the
pink and the green there?00:13:02
- Well, come, I'll show you.
- Okay, all right.00:13:03
- I'll come and show you.
- I'm just seeing00:13:04
so many cool things around here.00:13:06
I'm like, "What is that?00:13:07
Why does it look like that?"00:13:08
You just enter this room,
and I smell the wax.00:13:11
- Yeah, yeah.
- Smells like00:13:12
a candle factory in here.00:13:13
- Absolutely, so investment
casting is a really,00:13:15
really ancient technology.00:13:17
So our ancestors have been
doing investment casting00:13:19
to make jewelry, to make
weapons for millennia.00:13:22
We've just perfected it
here to make turbine blades.00:13:25
- It's so wacky.00:13:26
This is just not how I'd
expect it to happen at all.00:13:29
(intense music)00:13:30
Turbine blades strike me as one00:13:31
of the most high-tech things in the world.00:13:33
- Yep.
- And yet,00:13:35
this facility is using
wax as a starting point.00:13:39
- What you will see through
our tour today is that,00:13:42
actually, it's a really
highly technological process.00:13:45
(ominous music)00:13:46
This is our wax pattern die.00:13:48
This is how a turbine
blade starts its life.00:13:51
So, this is what's gonna
go inside the wax pattern,00:13:54
a ceramic core.00:13:55
This is gonna create a hollow
inside the turbine blade.00:13:59
So what's happening now is
we're injecting into the die.00:14:02
So that's the very start of
the life of a turbine blade.00:14:06
- That is really neat.
- What we'll actually see is00:14:08
that a lot of these features,
such as the aerofoil00:14:10
and the annular surfaces
are not touched further.00:14:13
So we will cast that, and
that will remain as cast00:14:15
as it goes into the engine.00:14:17
(ominous music) - [Derek] Every surface
here has to be perfect00:14:19
because this wax is what
will become the blade.00:14:22
- So Kim is our wax pattern assembler.00:14:26
So she's responsible for
taking the product straight00:14:29
from that die, making sure00:14:31
that things like die
lines have been removed.00:14:34
So where the die box come together00:14:35
and leave a small amount of flash,00:14:37
the operative word in all
of wax assembly is smooth.00:14:40
- [Derek] Every tiny imperfection
in the wax would become00:14:42
a flaw in the metal.00:14:43
So this takes an
incredible amount of skill.00:14:47
(ominous music) - Then it's the case of getting
that wax pattern attached00:14:49
to the unit runner to create the assembly.00:14:51
- I mean, the thought
that occurs to me, right?00:14:53
Shouldn't you be doing this with a robot?00:14:55
- Can, you know, like-
- Yeah, yeah, yeah.00:14:57
So, Rolls-Royce has facilities
that do this by robot,00:15:00
but our facility in particular
is very much focused00:15:03
on bringing in those new products.00:15:05
And it's far, far easier for
us to work with human beings00:15:09
to develop that method of
manufacture that's going00:15:11
to bring the next generation
of product through.00:15:13
- I'll bet, I can see the skill here,00:15:15
like it's phenomenal.
- Absolutely.00:15:16
- I'll just make a mess of it.00:15:17
- Absolutely, so would I.00:15:18
- Would you like a go?
- No. (laughs)00:15:21
(ominous music) Once the wax assembly is perfect,00:15:23
it's ready for the next stage.00:15:25
- Everything that is
wax is gonna become air,00:15:28
it's gonna become negative space, right?00:15:29
It's gonna become our cavity.00:15:31
And then we're gonna
fill that air with metal.00:15:34
(ominous music) So we take that wax assembly,
and we've gotta build a shell.00:15:38
(pensive music) Shell is made of many different layers.00:15:40
It's a zircon-based shell system.00:15:43
We're gonna dip into a primary story.00:15:45
It's really quite thin, like
a light syrup or a thin honey.00:15:48
- Oh yeah.00:15:50
(pensive music) - [Henry] And what that's
designed to do is map all00:15:51
of those really complex
geometric features.00:15:54
- Beautiful.
(engine droning)00:15:56
It's like making icing.00:15:58
- [Henry] So that's
actually the analogy we use.00:16:00
So, it's a bit like if you
put icing on top of a bun00:16:03
or a cake, you need to sprinkle it00:16:05
with some sugar afterwards,00:16:06
otherwise, it's all
gonna slop off the top.00:16:08
So we've got the slurry on there.00:16:09
We're gonna get a nice even
coat, drain it, make sure00:16:11
that it's an even thin layer.00:16:13
And then we're gonna sand,00:16:14
and that's then gonna
set that layer in place.00:16:17
- So cool.
(machine droning)00:16:19
Whoa.
(machine droning)00:16:21
We're then gonna dry it,00:16:22
so it's air-dried for many, many hours.00:16:24
And then we can create our backup layers.00:16:26
So our backup layers, it's
a much thicker slurry,00:16:28
more like a treacle,00:16:29
and the sand is much coarser,
more like a granulated sugar.00:16:32
And we're gonna maybe put four,
five, maybe even six layers00:16:35
to back up, because what
we need is we need a mold00:16:38
that can withstand00:16:39
that casting parameters that
we're putting in the die.00:16:41
You know, it's got a lot of work to do.00:16:44
- The wax is then melted out,00:16:47
and the mold is fired.00:16:48
Oh, yeah.00:16:50
(machine whooshing) That is wild.00:16:52
Cleaned and tested to make
sure there aren't any cracks.00:16:55
When it's done, this shell is
ready to hold molten metal.00:16:59
- This is a billet of alloy00:17:00
that's gonna fill the whole of that mold.00:17:02
So just that amount00:17:03
of metal is gonna fill
that whole mold there.00:17:05
- It doesn't look like an F.00:17:06
(ominous music)00:17:07
This is a nickel alloy.00:17:09
The first nickel alloys used
in jet engines were developed00:17:12
in the 1940s.00:17:13
By adding chromium and cobalt,00:17:15
engineers created alloys
that could handle 80000:17:18
to 900 degrees Celsius,00:17:20
around 100 degrees hotter
than the steel used before.00:17:23
And these alloys could keep
their strength for thousands00:17:26
of hours, a tenfold improvement in life.00:17:29
But the real breakthrough
came when they added00:17:31
a touch of aluminum.
(film whirring)00:17:33
So we wanted to see00:17:34
how it held up under
the same lab conditions00:17:36
as the steel and titanium.00:17:38
- [Emilia] What temperature are we in now?00:17:40
- [Howard] Oh, that's 700 degrees.00:17:43
- [Emilia] 700, so the steel's long gone.00:17:44
- Steel's, long gone.00:17:45
That's 800 degrees.00:17:46
800, yes.
(flames blasting)00:17:48
- [Derek] In around this temperature,00:17:50
it's actually getting stronger.00:17:53
(ominous music) So why would heating a
metal make it stronger?00:17:56
Well, when these nickel
alloys were first used00:17:58
in jet engines, no one actually knew.00:18:01
But about 10 years later,00:18:02
electron microscopes had
improved enough for engineers00:18:05
to finally see what was happening inside.00:18:08
(ominous music) As we zoom in on the
alloy, a pattern emerges.00:18:12
The microstructure isn't uniform.00:18:14
Instead, it kind of looks like
a city grid made up of blocks00:18:18
with rods in between them.00:18:20
Only, each block is so small,00:18:22
over 300 would line up across
the width of a human hair.00:18:26
(ominous music) Now, surprisingly, both the rods00:18:28
and the blocks are made up
of the exact same atoms,00:18:30
mostly nickel with a little aluminum.00:18:33
They even have the same crystal structure,00:18:35
a grid of tiny cubes with
atoms sitting at the corners00:18:38
and at the center of each face.00:18:40
The only difference is00:18:41
that the atoms are arranged
slightly differently.00:18:44
In the road structure,00:18:45
the aluminum and nickel can take any spot.00:18:48
There is no repeating
sequence from cube to cube.00:18:51
And this is known as the gamma phase.00:18:53
But in the blocks, aluminum
always takes the corner spots,00:18:57
and nickel the faces,00:18:59
and you get a perfect repeating
pattern cube after cube.00:19:02
This is the gamma prime phase.00:19:04
And it's this difference00:19:05
that is crucial when a
dislocation tries to glide00:19:08
through the lattice.00:19:09
In the rods, this motion is easy.00:19:11
Each layer of atoms can
shear smoothly past the next,00:19:14
leaving the structure
looking unchanged behind it.00:19:17
But if you try to do the
same thing in the blocks,00:19:19
well, now you're actually
changing the order of the atoms,00:19:22
nickel and aluminum end up
sitting in the wrong places.00:19:26
That takes energy, so
the lattice resists it.00:19:29
So, when a dislocation moving00:19:30
through the rods hits
a block, it gets stuck.00:19:33
And that's what makes
this alloy so strong.00:19:35
- [Henry] But if you keep pushing00:19:37
and the stress gets high enough,00:19:38
dislocation can finally force its way in.00:19:41
The catch is that this
dislocation leaves the lattice00:19:43
in such a high-energy
mess that the only way00:19:46
that it can keep moving
is if there's a second one00:19:48
right behind it that puts
things back in order.00:19:51
So in the gamma prime
phase, dislocations have00:19:53
to travel in pairs,
called super dislocations.00:19:56
- I need that creation of
those super dislocations,00:20:00
and I need that very high
stress to be able to shear.00:20:02
So that's why the strength is very high00:20:04
relative to other alloys.00:20:06
What happens is, ultimately,00:20:07
because you're shearing
through that gamma prime00:20:10
with two dislocations,00:20:11
as the temperature continuously increases,00:20:13
you're adding more and more
thermal energy in the material.00:20:15
What happens is the
atoms are gonna vibrate00:20:16
more and more and more.00:20:17
So there's a likelihood, as I'm doing this00:20:20
and I'm oscillating in three dimensions,00:20:22
that the thermal energy is gonna drive me00:20:25
to actually slip down rather
than just slip in one plane.00:20:29
So, now, if one cross slips,00:20:31
they're no longer on the same plane.00:20:32
Think of it as if we're standing in line,00:20:35
and the only way that you can
move is I push you, right?00:20:38
And then, I keep on pushing you,00:20:39
and then suddenly, you drop.00:20:40
So if I now try to push you,
I cannot find you, right?00:20:43
You're not in front of me anymore.00:20:44
Your shoulders are now below me.00:20:46
- Well, how do you touch 'em? (laughs)00:20:49
(Jaafar laughs) - I should have used the
other example, you pushing me.00:20:51
But anyway.
(both laughing)00:20:53
But it's exactly that.00:20:55
It's the exact same analogy.00:20:56
There's nothing to push me anymore.00:20:57
There's like, I am not able to do it.00:21:00
(ominous music) - So now you've got these two dislocations00:21:02
that are on different planes,00:21:03
so they can't travel together anymore.00:21:05
And as a result, they're
both now locked into place.00:21:08
And you can see that effect on this graph.00:21:10
While steel and titanium
strength drops off,00:21:12
in the nickel super alloy,
you actually get a peak.00:21:15
That's because the extra thermal energy00:21:17
lets more dislocations
cross-slip and get separated.00:21:20
And it's that that shuts down
the motion of dislocations.00:21:23
But if gamma prime is so strong,00:21:26
why don't we just make the
entire turbine blade out of it?00:21:29
Well, that strength comes at a cost.00:21:30
Gamma prime stops the
dislocation so effectively00:21:33
that it becomes brittle.00:21:35
All it takes is one
crack or a sudden impact,00:21:37
and it could lead to a sudden failure.00:21:40
So the real trick is in
striking the right balance00:21:42
between enough gamma prime
to trap the dislocations00:21:45
and to prevent this creep,00:21:46
but also enough gamma to
keep the alloy ductile,00:21:49
so that it can bend without breaking.00:21:51
- [Derek] And in our test,00:21:52
you can see exactly how that plays out.00:21:55
- A 1,000 degrees, and still nothing.00:21:57
- Still nothing.00:22:00
(ominous music)
(mold clanks) - [Howard] There we go.00:22:01
- [Emilia] Oh my gosh.00:22:03
(suspense music) - [Howard] That's 1,100 degrees C.00:22:07
- It's stretching.00:22:10
(suspense music) I mean, it's still holding up like-00:22:12
- It's doing a good job.00:22:13
That's 1,200 degrees C.00:22:16
- [Emilia] 1,200. (laughs) - [Howard] That's the
temperature program that stops.00:22:19
And it's still surviving.00:22:21
- [Emilia] Still going. - But if you push the temperature too far,00:22:24
even this alloy reaches its limits.00:22:26
Cross-slip becomes easier.00:22:27
The paired dislocations can now hop00:22:29
between the planes together,00:22:31
and the ordered cubes of gamma
primes start to dissolve.00:22:34
So the dislocations break free,00:22:36
and it finally gives out.00:22:37
- [Howard] Oh, it may
have just, did it break?00:22:39
- Oh, yeah, yeah, it did, it broke.00:22:41
- But strength alone isn't what
makes these alloys special.00:22:45
When you heat up the alloy,
aluminum at the surface reacts00:22:48
with oxygen to form a
thin continuous layer00:22:50
of aluminum oxide.00:22:52
Unlike the brittle oxides00:22:53
that form on other materials
like steel or titanium,00:22:56
this layer stays intact
at high temperatures,00:22:59
protecting the metal below.00:23:01
(suspense music) And by adding other elements,00:23:03
we can tune these super alloys.00:23:05
Each one brings a specific
property that we want.00:23:08
Most modern super alloys contain as many00:23:10
as 10 different elements,00:23:12
all carefully balanced in
their relative abundances00:23:14
for the desired properties.00:23:16
Chromium improves resistance
to oxidation and corrosion.00:23:20
Cobalt, titanium, niobium, tantalum,00:23:22
and vanadium help stabilize
the gamma prime phase.00:23:25
Molybdenum and iron
strengthen the gamma matrix.00:23:28
And then there's rhenium.00:23:30
Rhenium has one of the
highest melting points00:23:32
of any metal at 3,180 degrees Celsius.00:23:35
It's second only to tungsten.00:23:37
In the nickel super alloy,00:23:39
It slows the atomic-scale rearrangements,00:23:41
enhancing the alloy's resistance00:23:42
to deformation even at temperatures00:23:44
above 1,000 degrees Celsius.00:23:46
It's one of the rarest
elements in the Earth's crust00:23:49
at less than one part per billion.00:23:52
And more than 80%00:23:53
of what we mine ends up
right here in jet engines.00:23:58
(ominous music) - But even with these
advancements in alloy chemistry,00:24:01
there's still one fundamental problem.00:24:04
And that's that metals are crystalline.00:24:06
Any metal you see from the
tip of this ballpoint pen00:24:09
to the spoon in my coffee cup,
they're all actually made up00:24:13
of millions of little
crystals stuck together.00:24:16
It's kind of like grains
in the sugar cube.00:24:18
If I crush it...00:24:21
(ominous music) It's not like I've broken
any individual crystal,00:24:24
I've just broken them apart.00:24:26
It's the boundaries between the grains00:24:28
that are the weak point.00:24:29
And it's the same thing in a metal.00:24:31
(ominous music) - So, if we zoom out from the gamma00:24:33
and gamma prime structure,
it looks something like this.00:24:36
One crystal is basically a
three-dimensional lattice00:24:39
of atoms all lined up
in the same orientation.00:24:41
But the crystals themselves are00:24:43
all in different orientations.00:24:45
So where they meet, their
lattices don't line up.00:24:47
And that mismatch leaves more
open spaces and broken bonds.00:24:51
And you also get defects there,00:24:53
like vacancies and impurities,00:24:55
all of which make grain
boundaries the weakest point.00:24:58
And this also has another consequence.00:25:00
It makes it easier for atoms
to move along the boundaries.00:25:04
They become kind of super
highways for atomic diffusion.00:25:07
This becomes even more00:25:08
of a problem at high
temperatures when atoms have00:25:10
more energy to move around,00:25:12
add stress like the
massive centrifugal loads00:25:15
on a turbine blade, and the
grains can actually start00:25:18
to slide past each other.00:25:20
The whole structure slowly
deforms, stretching,00:25:23
almost like warm taffy.00:25:25
(ominous music) As long as it has grains
in it, it will creep,00:25:28
and fail far more easily.00:25:30
And that's a really hard problem to solve00:25:32
because normally, as a molten alloy cools,00:25:35
tiny crystals start to form
all throughout the liquid.00:25:38
So you have to find some
way to control them.00:25:41
- This is one of our furnaces.00:25:43
They're all induction-heated,
there's no kind of gas, fire,00:25:46
or anything like that, and
they're all under vacuum.00:25:48
So, we only cast to the
vacuum in the absence00:25:50
of any atmosphere, but
particularly oxygen,00:25:52
which is obviously metallurgically
gonna cause us all kinds00:25:54
of problems with oxides.00:25:56
- [Derek] You start by
pouring molten super alloy00:25:58
into a ceramic mold
that's mounted vertically00:26:00
and heated to about the same
temperature as the melt.00:26:03
The mold fills from the
root up toward the tip.00:26:06
At the very bottom of the mold sits00:26:08
a copper plate cooled by water.00:26:10
Its surface is patterned
with tiny grooves that act00:26:12
as nucleation points00:26:13
for the first crystals to start to form.00:26:16
It's here that solidification begins.00:26:18
Then, the entire mold is slowly
lowered out of the hot zone,00:26:22
so the solidification continues
in just one direction.00:26:25
- It's a very slow process
in the magnitude of hours.00:26:29
Once that's finished,00:26:30
the whole machine will then index round,00:26:32
and it will push the completed mold00:26:34
up out of the other side.00:26:36
- Oh.00:26:37
(machine humming) Wow.00:26:38
- So our casting temperatures are00:26:40
roughly 1,500 degrees Celsius.00:26:42
- It's kind of at the same
temperature now as it would be00:26:45
inside the jet engine.
- Exactly.00:26:47
- It's absurd, they like,00:26:48
you're making the turbine blades00:26:49
at the same temperature
that they're gonna operate,00:26:51
but they like, here, they're liquid.00:26:53
(ominous music) Now, if we just did that
on its own, you'd end up00:26:56
with a blade that looks like this.00:26:59
(ominous music) - Here's a directionally solidified blade.00:27:02
And what you can probably
see there is the contrast00:27:05
between the grains.00:27:07
These are all different crystals,00:27:08
but they're all running
on this axis of the blade,00:27:12
which makes it significantly stronger00:27:14
than an alloy that is cast,00:27:16
where all of the crystals
are separate from each other.00:27:18
- So those are like individual crystals.00:27:20
- [Henry] These are individual
crystals, yeah, absolutely.00:27:23
So we are looking at-
- Wow.00:27:25
- At crystals on kind of a macro level,00:27:27
where normally, we'd be talking00:27:28
about crystals on a micro level.00:27:31
(ominous music) - In a rotating turbine,00:27:33
the blade is being
pulled along its length.00:27:35
With columnar crystals all
lined up along this span,00:27:38
the blade can carry those
stresses far more effectively.00:27:41
There are no grain boundaries00:27:42
that cut across the blade,
creating weak points00:27:44
for it to crack.00:27:45
But scientists have found
a way to do even better.00:27:48
If you introduce a bend in the mold00:27:51
just above the chill plate,
something strange happens.00:27:54
The number of columnar
crystals that make it00:27:56
through drops sharply.00:27:58
And if you add another
bend, even fewer survive.00:28:02
(ominous music) So, engineers added a
helical passage known00:28:05
as the pigtail here at
the bottom of the mold.00:28:07
- The pigtail is doing the job
to select the single crystal.00:28:11
The spiral is gonna choke out
every other grain bar one.00:28:15
So we're only gonna have one
grain that is then gonna grow00:28:18
through the entirety of that blade,00:28:21
and cast that blade as a single crystal.00:28:23
Or at least, that's the theory.00:28:25
- That's crazy.00:28:26
- So this is a starter
attached to a spiral00:28:29
that we've etched so that we
can reveal that structure.00:28:31
So you can see down at the
bottom, we are starting00:28:35
to grow directionally solidified grains.00:28:38
But as we get up here, we can start to see00:28:40
that we're growing
directionally solidified grains.00:28:43
And then, as we're going up the spiral,00:28:47
the grains are starting to be choked out00:28:48
by the upper surfaces of that
spiral until, when we get00:28:51
to the top, we're just
as a single crystal.00:28:54
And then, that then allows that00:28:55
to grow right the way through the blade.00:28:57
- Yeah, that's amazing.00:28:58
- And what we should end up
with is a blade like this.00:29:01
So this is a blade of a single crystal.00:29:04
It's a really impressive thing to look at.00:29:07
(ominous music) The shimmer is beautiful.00:29:08
- Yeah.00:29:09
- Even after the blade solidifies,00:29:11
it's still not ready for the engine.00:29:13
It's heated again, almost
to its melting point.00:29:16
And that might sound risky00:29:17
because we've spent all
this time making sure it's00:29:19
a perfect single crystal.00:29:21
But this heating step lets
the atoms shuffle around00:29:24
just enough to spread out evenly,00:29:27
and form the final desired
microstructure of the gamma00:29:30
and gamma prime phases00:29:31
that make these super alloys so strong.00:29:34
- And as if casting, as a
single crystal is not enough,00:29:37
actually, the orientation
of that crystal is00:29:40
also of paramount significance.00:29:42
So you may have cast
this as a single crystal,00:29:45
but if the crystal orientation is off00:29:48
by a certain amount,00:29:49
you get completely
different stress responses00:29:52
within that blade.00:29:53
- Today, after decades
of development, over 95%00:29:57
of blades can be cast
successfully as single crystals.00:30:01
Just think about how incredible that is.00:30:04
We've gone from a turbine blade
that contained on the order00:30:06
of 50,000 crystal grains down to just one.00:30:10
When we grow these things,
they don't solidify00:30:13
as a uniform front.00:30:15
On a microscopic scale,00:30:16
the solidification front
looks like a forest00:30:19
of tiny tree-like
branches called dendrites00:30:22
that are pushing their
way into the liquid.00:30:24
At first glance, it looks
messy, like millions00:30:27
of separate trees jostling for space.00:30:30
There are up to 10 elements in there,00:30:32
each with its own density
and melting point.00:30:35
Yet somehow, every one
of those trees is locked00:30:39
into the exact same crystal lattice.00:30:42
So the final crystal is comprised
of more than six times 1000:30:46
to the 24 atoms,00:30:47
that is more stars than there are00:30:50
in the observable universe.00:30:51
When all these atoms are
repeating the same pattern,00:30:55
perfectly aligned from root to tip,00:30:58
this completely transformed
what jet engines can do.00:31:01
Single-crystal blades
can withstand stresses00:31:03
and temperatures that would
destroy ordinary alloys.00:31:06
They last up to nine
times longer against creep00:31:09
and thermal fatigue,00:31:10
and are more than three
times more resistant00:31:12
to corrosion than blades
made from multiple grains.00:31:15
That's why modern jet engines
can now run for 25,000 hours00:31:19
between major overhauls,00:31:21
something that would've been unthinkable00:31:22
before single crystal blades.00:31:25
(suspense music) And the impact has been huge.00:31:27
Between 1960 and 2010,00:31:29
jet aircraft became about
55% more fuel efficient.00:31:33
And a huge part of that
improvement comes down00:31:35
to advances in these nickel super alloys.00:31:38
Back in the 1960s,00:31:40
flying was a luxury few could afford.00:31:42
A one-way flight from New York00:31:43
to Paris would set you back $310,00:31:46
which is about $3,750
adjusted for inflation.00:31:50
But as engines became more efficient,00:31:52
able to handle hotter cores00:31:54
and equipped with much larger fans,00:31:56
airlines could carry more
people farther using less fuel.00:32:00
So, tickets got cheaper
and air travel exploded.00:32:03
Today, at any given moment,
there are roughly 10,00000:32:06
to 14,000 planes in the sky.00:32:08
That scale of movement is possible00:32:10
because of these turbine blades.00:32:15
(jet hovering) In the furnace, the nickel
super alloy outperforms00:32:18
all the other samples,00:32:19
surviving up to 1,200 degrees Celsius.00:32:22
But wait, that's still 300 degrees less00:32:24
than the temperature inside a jet engine.00:32:27
So why don't the blades melt?00:32:29
Well, there are two
final layers of defense.00:32:32
The first is built into the
shape of the blade itself.00:32:35
- We then have to leach the core out.00:32:37
So we do that in a caustic solution00:32:40
of potassium-sodium
hydroxide under pressure00:32:44
and temperature to leach the core out,00:32:47
that will leave those core
passages completely empty.00:32:51
- [Derek] And those
passages are the real secret00:32:53
to the turbine blade survival.00:32:54
- So as the air's flowing
through, it is turbulent,00:32:58
and as such, it can remove much more heat00:33:00
from the surface of the blade.00:33:01
- Yeah.
- Than it was.00:33:03
- Is it these ridges here
that we're talking about?00:33:04
- Exactly, yeah, yeah, these ridges here.00:33:05
- [Derek] They're intentional
to the trip the flow into-00:33:08
- Trip and turbulate that air
flow so that it's removing00:33:11
as much heat as possible from the metal.00:33:13
So then we get onto the really juicy part,00:33:15
which is film cooling.00:33:16
So we talked about the
ice cube in the ovens00:33:18
that keeping our blades
as cool as possible.00:33:21
So this is where we start to drill in00:33:23
what we call film cool holes.00:33:25
And what we're aiming
to do is we're aiming00:33:27
to get into those cooling passages.00:33:29
So we saw that core earlier on.00:33:31
They are the cooling passages inside.00:33:34
And these holes have got00:33:35
to get right into those cooling passages00:33:37
to allow the air to come out.00:33:39
And the air is then gonna blow
as a film over the surface00:33:42
of the blade, a film-cool
hole to create a film00:33:46
of air, which is preventing00:33:47
that metal from melting
in those temperatures.00:33:50
- This cooling air isn't exactly cold.00:33:54
It actually comes from the
high-pressure compressor section00:33:56
of the engine at around
600 degrees Celsius.00:33:59
But that is cool enough00:34:00
to help keep the blades from melting.00:34:02
But it's still not quite enough.00:34:04
And you can't just add more cooling air00:34:07
because every extra bit of air
you use from the compressor,00:34:10
you lose from thrust,00:34:12
and actually make the
engine less efficient.00:34:14
So every turbine blade is also coated00:34:17
with two protective layers.00:34:19
First, a thin metallic bond
coat that resists oxidation,00:34:23
and then a ceramic topcoat.00:34:25
Even though it's only about a
quarter of a millimeter thick,00:34:28
this ceramic coating can
keep the metal beneath it00:34:31
100 to 170 degrees cooler
than it would otherwise be.00:34:35
And this is the final barrier00:34:36
that stops the blades from melting.00:34:38
So, now we've got this
insane piece of engineering00:34:41
that can survive the 1,500-degree gas.00:34:44
The intense load and the oxidation
problem should be solved.00:34:49
Well, it would be, except for one thing,00:34:53
(ominous music) - At 36,000 feet, you
wouldn't believe this,00:34:56
but there's dirt and
dust in the atmosphere00:34:59
that our engines are ingesting.00:35:02
(ominous music) The dirt and dust comes,
it sticks on the blades,00:35:04
but it also goes through
the whole cooling circuit,00:35:08
and it walks the cooling
from getting through00:35:11
to cool the blades, and
then the blades burn up.00:35:15
Usually, every time I get on a plane,00:35:17
I'm thinking, "This is
never gonna work." (laughs)00:35:19
No, I mean it's incredible
how an engine can work00:35:23
'cause there's so many moving
pieces, there's so many parts00:35:25
to the environment, so terrible.00:35:27
And now, we have this dust
and dirt, which is really bad.00:35:31
(intense music) - I am at Testbed 80,00:35:33
and they're about to
fire up this jet engine00:35:36
and then throw dust into it.00:35:39
The same stuff that makes
up sand and volcanic ash,00:35:42
exactly what real engines
encounter in flight.00:35:44
- So this engine is the 97K.00:35:47
It goes on the A35000:35:48
and is our high-thrust version of that.00:35:50
So 97,000 pounds of thrust is
what this engine's producing.00:35:54
When we're running a bit
an engine like this, we try00:35:56
and carefully recreate exactly
what happens in service,00:36:02
(intense music) - How much dust goes00:36:03
in the engine?
- Not very much.00:36:05
It was surprising when I found out00:36:06
exactly how much we put in.00:36:07
It's in the order of
tablespoons worth per cycle.00:36:11
- So, I (indistinct) master on.00:36:13
Condition power on.00:36:16
(fan swooshing) (buttons clicking) Master fuel lever on.00:36:17
Start request in three, two, one.00:36:20
Now.
(computer beeps)00:36:28
(intense music) (blades swooshing) - So, what does the dust
actually do inside a jet engine?00:36:31
- So, once it goes through to
the hot section of the engine00:36:34
and hits kind of turbine
blades, it's gonna be melted.00:36:37
And so, it sticks to the outside
of our turbine components00:36:41
and it slowly rips layers00:36:43
of that thermal barrier coating off.00:36:46
And then, you lose your
temperature reduction00:36:49
that comes from the barrier coating,00:36:51
so that your nickel alloy
underneath it gets hotter00:36:53
and hotter, and that's when it starts00:36:54
to deteriorate the turbine.00:36:58
(blades swooshing)00:37:01
- That's why engineers at
Rolls-Royce are still refining00:37:04
these blades, developing new
ceramic coatings designed00:37:07
to resist mold and dust,00:37:08
and extend the life of
the turbine by up to 30%.00:37:12
That's just the latest step in a story00:37:13
that's been unfolding for decades.00:37:15
These blades have been refined00:37:17
and perfected to the point00:37:19
where they operate right at the edge00:37:21
of what is physically possible.00:37:23
You're always on a knife-edge,
pushing every material,00:37:26
every process to the
limit to build an engine00:37:28
that can do the seemingly impossible,00:37:30
run hotter than its own melting point.00:37:33
The more I learned about
the brutal environment00:37:35
these blades have to
survive, the more it felt00:37:38
like they shouldn't work at all.00:37:40
And yet, they do.00:37:42
Every day, these machines
carry millions of people00:37:45
across the world and we barely
stop to think about them,00:37:48
they're a monument to human ingenuity.00:37:51
What happens when we refuse00:37:52
to accept limits, when
we turn the impossible00:37:55
into the routine?00:38:01
(ominous music) (scene change zooms)
(ominous music) I can't grow a single-crystal
turbine blade in my kitchen,00:38:05
but with the help from
this video sponsor, KiwiCo,00:38:07
I can grow a crystal garden with my kids.00:38:11
This month, they sent us their
Crystal Garden Chemistry Kit.00:38:14
We set everything in place,
mixed up the chemical solution,00:38:16
and then watched as
colorful crystals started00:38:19
to bloom over the next 48 hours.00:38:21
Every few hours, my kids
would run back to check00:38:23
how much the garden had grown.00:38:25
They were totally fascinated,00:38:26
and it sparked so many
questions about crystals00:38:29
and atoms, how things arrange.00:38:31
Pretty soon, we were talking00:38:32
about how metals are crystalline, too,00:38:34
and setting ourselves the challenge00:38:36
of growing one giant
crystal turbine-blade style.00:38:39
(camera shuttering) I love how simple KiwiCo makes this.00:38:42
Everything we needed
came right in the box,00:38:44
so we could just open it up00:38:45
and dive straight in,
doing the experiment.00:38:48
And it's not just chemistry.00:38:49
They've got crates for robotics,00:38:51
engineering, art, design
techniques, and so much more.00:38:54
There is something for
every age and interest.00:38:57
(scene change chimes) KiwiCo crates also make a
great gift for the holidays.00:39:01
It's creative, hands-on,00:39:02
and gives kids something
they can actually make00:39:04
and be proud of.00:39:05
- They're kind of messy.
- Mm-hmm.00:39:08
- And like hard to make, but not too hard,00:39:12
but hard enough to make it fun.00:39:14
- So if you wanna try out KiwiCo,00:39:16
click the link in the
description or scan this QR code.00:39:19
Use my code Veritasium00:39:20
to get 50% off your first monthly crate.00:39:23
I wanna thank KiwiCo for
sponsoring this video,00:39:25
and I want to thank you for watching.Description:
How does a jet engine not melt? Sponsored by KiwiCo - Use code VERITASIUM to get 50% off your first monthly KiwiCo Crate! https://www.kiwico.com/VERITASIUM Want to start your own crystal garden? https://www.kiwico.com/crystalchemistry Our friends at Science Alert are doing a sweepstakes where you can win a 5-day space themed vacation for two. The itinerary includes a trip to the Kennedy Space Center in Florida for astronaut training and a meet and greet with a NASA astronaut. If you’d like to be entered in the draw, just subscribe to their free science newsletter Spark. No purchase necessary. Open to US residents only. Enter here: https://www.sciencealert.com/newsletter We have a tabletop game launching! Check it out here! - https://www.kickstarter.com/projects/elements-of-truth/elements-of-truth-by-veritasium?ref=bgt9se If you’re looking for a molecular modelling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://snatoms.com/ Sign up for the Veritasium newsletter for weekly science updates - https://www.veritasium.com/newsletter ▀▀▀ 0:00 How a jet engine works 3:18 Why are jet engines so big? 5:17 The Inside of a Jet Engine 8:49 Edge Dislocation 11:11 The First Jet Engine 12:48 Inside the Rolls-Royce Precision Casting Facility 17:07 Nickel Superalloys - Gamma Prime 23:58 Crystal Structure 25:38 Making a Turbine Blade 32:22 Why don’t turbine blades melt? 35:30 Throwing Sand Into a Jet Engine ▀▀▀ A big thanks to Ben Todd, James Banks, Ben Fifoot, Doug Smith, Stefan Wagner, Rumaanah Hoosen and the rest of the team at Rolls-Royce. A huge thanks also to Professor Howard Stone and Dr George Wise from the University of Cambridge. We’re also incredibly grateful to Professor Jaafar A. El-Awady, Dr Karen A Thole, Professor Cathie Rae, Professor Paul Withey, Professor Pedro Patrício, Professor José Tavares and Ryan Moreman for their time and expertise. Thanks to Institute for Materials, Ruhr University Bochum, SFB Transregio 103 for the animation showing the microstructure of the nickel superalloy. Full youtube video here - https://www.youtube.com/watch?v=wYHch5QIWTQ Thanks to Professor Hongbiao Dong for the animation showing the grain selection in a single crystal turbine blade. Full youtube video here: https://www.youtube.com/watch?v=br9iaeYYxSM References: https://docs.google.com/document/d/1Nd3KqiBy7v54U9HcMqFFcCnVMPVqreXngbioLAL4tvs/edit?tab=t.0 ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Albert Wenger, Alex Porter, Alexander Tamas, Anton Ragin, Anupam Banerjee, armedtoe, Bertrand Serlet, Blake Byers, Bruce, Dave Kircher, David Johnston, David Tseng, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, Hayden Christensen, Ibby Hadeed, Jeromy Johnson, Jon Jamison, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, meg noah, Michael Bush, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Robert Oliveira, Sam Lutfi, Tj Steyn, Ubiquity Ventures & wolfee ▀▀▀ Writers - Emilia Gyles, Casper Mebius & Derek Muller Producer & Director - Emilia Gyles Presenters - Derek Muller & Henry Van Dyck Editor - Trenton Oliver Camera Operators - Jack Coathupe, Justin Wood, Emilia Gyles, Henry Van Dyck & Derek Muller Animators - Mike Radjabov, Emma Wright & Fabio Albertelli Additional Editors - James Stuart & Peter Nelson Researcher - Aakash Singh Bagga Thumbnail Designers - Ren Hurley, Ben Powell & Abdallah Rabah Production Team - Josh Pitt, Matthew Cavanagh, Anna Milkovic & Katy Southwood Executive Producers - Casper Mebius & Derek Muller Additional video/photos supplied by Getty Images, Storyblocks Music from Epidemic Sound
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