
Super-hard metal 'four times tougher than titanium' - Jerry2
http://www.bbc.com/news/science-environment-36855705
======
amluto
The BBC article heavily confuses hardness and toughness. The researchers seem
to care about hardness here.

The actual paper
([http://advances.sciencemag.org/content/2/7/e1600319.full](http://advances.sciencemag.org/content/2/7/e1600319.full))
is much better and is free.

~~~
pcl
Toughness is a new term for me. From [1]:

 _Hardness is a characteristic of a solid material expressing its resistance
to permanent deformation. The Rockwell or Vickers hardness scales are most
commonly used in the industrial blade industry.

Toughness on the other hand is the maximum amount of energy a material can
absorb before fracturing, which is different than the amount of force that can
be applied. Toughness tends to be small for brittle materials, because it is
elastic and plastic deformations that allow materials to absorb large amounts
of energy._

[1] [http://americancuttingedge.com/hardness-vs-
toughness/](http://americancuttingedge.com/hardness-vs-toughness/)

~~~
StavrosK
Does this mean that plastic is very tough and hard?

Edit: Sorry, not plastic. I meant rubber.

~~~
bearbin
No, plastic can be very tough, but is not generally very hard (although there
are exceptions to both).

Since plastic can stretch a large amount before breaking it absorbs more
energy than a (inverse of tough) object, so it is tough.

Since it is easy to stretch inelastically, it is not hard.

~~~
dragontamer
Plastics are... plastic. Uggghhhhh....
[https://en.wikipedia.org/wiki/Plasticity_(physics)](https://en.wikipedia.org/wiki/Plasticity_\(physics\))

Usually anyway. IIRC, Acrylic is a plastic that shatters instead of deforming.
But most plastics (ABS (aka Legos), polypropylene (PP, #5 Plastic), Pete (most
bottles), HDPE (aka cutting boards)) all are "plastic", as in having high
plasticity.

IIRC, metals are actually more "plastic" (deform more before breaking) than
erm... plastics. See iPhone aluminum bending issue for details.

~~~
jrapdx3
I recall that "plastic" was so named because of the material's formability.
Thermoplastics soften or liquefy when heated, becoming malleable and can be
molded or extruded, retaining shape when cooled. Thermosetting types are
products that are cured by heat, UV or chemical reaction, having high
plasticity before curing but irreversible rigidity after.

"Plastics" are mostly petrochemical derived organic polymers. Properties of
some, like acrylic glazing are relatively hard and brittle, others quite
elastic and soft, e.g., foam rubber. Obviously modern life is utterly
dependent on these materials which are employed in virtually everything we use
from food to space probes.

There are good reasons to believe that production of "plastics" is among the
highest and best use of petroleum resources, it's a shame we continue burning
it up at a prodigious rate. Trends to find alternative energy sources would
have benefit in this respect too.

~~~
dredmorbius
The history of plastics discovery is pretty interesting too.

The first were based on coal tar, starting around 1870-1880 IIRC. Then came
bakelite, still used in cookware handles -- it has exceptionally good thermal
resistance properties.

Discovery accelerated through the 1900s, 1910s, and 1920s, and exploded in the
1930s, with the number of materials about doubling IIRC.

Names started changing too -- from chemical (polypropelene, polyester,
polystyrene) to brand (nylon, teflon, orlon).

I've also noted that with both coal and oil, there seems to have been an
adoption and technological development cycle in which the first use was to
burn the materials, and only later, by some decades, did the chemistry develop
for _materials_ based on the substrates. There's probably a lesson here.

------
valarauca1
Link to paper
[http://advances.sciencemag.org/content/2/7/e1600319](http://advances.sciencemag.org/content/2/7/e1600319)

Link to PDF of paper
[http://advances.sciencemag.org/content/advances/2/7/e1600319...](http://advances.sciencemag.org/content/advances/2/7/e1600319.full.pdf)

------
andyidsinga
"Conventional knee and hip implants have to be replaced after about 10 years
due to wear and tear."

this is really amazing to me! you put metallic, designed-to-last object inside
an organic blend of tissue and bone and human activity and in 10 years its
worn out. So much opportunity in the area!

Along the same lines, interesting how delicate our bodies are in the short
term but rather durable in the long term.

~~~
Aelinsaar
Your own body basically goes through a skeleton every 7 years, although it's a
gradual procedure of course. Your bones are constantly being eaten away, and
replaced as part of their maintenance. It's truly amazing, but the secret is
definitely, "We can rebuild it" not "Unbreakable".

~~~
aluhut
We should adjust our justice systems to this cycle. You can sit in jail for
max 7years. After that you are considered a different person. The justice
apparatus needs to use that 7 years to form this new person in a way that it
can behave according to the outside system.

~~~
andyidsinga
There's something to what you're saying here! - the justice system, and the
people involved with it need a real change in mindset.

It isn't that you might be a different physical person after 7 years, but a
different person based on the current context!

There was a great invisibilia podcast on the subject :
[http://www.npr.org/programs/invisibilia/482836315/the-
person...](http://www.npr.org/programs/invisibilia/482836315/the-personality-
myth?showDate=2016-06-24)

See also (referenced in podcast) :
[http://www.columbia.edu/cu/psychology/indiv_pages/mischel/Wa...](http://www.columbia.edu/cu/psychology/indiv_pages/mischel/Walter_Mischel.html)

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scentoni
Since it's 58% gold by weight, just the raw materials cost is going to be
high. I expect for most applications it will be used as a thin coating over
titanium or some other material. I wonder if it's a good choice for jewelry.
Phase diagram: [http://www.himikatus.ru/art/phase-diagr1/Au-
Ti.gif](http://www.himikatus.ru/art/phase-diagr1/Au-Ti.gif)

------
tsomctl
> Titanium is one of the few metals that human bone is able to grow around
> firmly, allowing it to be used widely in medicine and dentistry.

How good are we at concentration gradients in alloys? For a replacement joint,
say, could the part that the bone bonds to be mostly titanium, and then the
bearing portion be this new alloy?

~~~
GarrisonPrime
Although I've only spent a few weeks in an ortho rotation in med school, I
think pretty good. Many implants are coated with silver to help prevent
infections. I've never heard of such silver layers ever "peeling off" or
somesuch, so it seems the silver/titanium mix is effective.

~~~
Roboprog
The silver oxidizes and disappears after a while (few weeks?) though, right?
(probably by design)

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zeristor
How does one recycle the gold once the patient has deceased?

This has just raised what you can afford when you're paying with an arm and a
leg.

~~~
zeristor
Thinking about this perhaps the Titanium gold would be a surface layer or
coating over Titanium.

No doubt there would be metallurgical issues with this.

Funnily I had a pre-student job in a coatings company using detonation guns to
fire tungsten carbide into metals in order to make them tougher. Could a
similar treatment be used for Titanium hip replacements?

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Mizza
I bet we'll see this coating golf clubs and tennis rackets (for absolutely no
reason) quite soon!

~~~
Coincoin
Now 30% stronger. Same material as used in aeronautic and surgical field.
Military grade!

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avs733
After the long discussion in the 'alcohol causes cancer' thread I will admit
to being a bit suspicious of science journalism.

~~~
Turing_Machine
Just now? :-)

Seriously, science journalism is almost uniformly horrible (as is just about
every other type of journalism -- google "Gell-Mann Amnesia Effect").

~~~
avs733
I would disagree with the 'almost uniformly' but I understand your point. I
would tend to exempt arstechnica for example.

I feel like most of the issue comes when journalists comment or repurpose
journal articles. What seems to get dropped is the background, the context,
and the limitations that are often expressed in a nuanced language. In the
end, as a scientist, I blame scientists...you created the knowledge, try and
take some ownership of it (having been in the situation myself).

------
ftwtitanium
An alloy of gold and titanium? Iron Man anyone?

~~~
sevenless
With the bio-compatibility, it'd work better for Wolverine.

~~~
Roboprog
Well, titanium has a a lot of strength relative to its weight, but I think you
might need some kind of tungsten alloy for your budding weapon X program :-)

I have no idea how toxic tungsten is, buy hey, it's Wolverine, right?

------
murbard2
Surely this can't be the firs time someone thinks of making a gold titanium
alloy. What did the previous attempts miss?

~~~
the8472
Other mixes of Au/Ti have been made and used. There is plenty of prior
research which the paper also cites.

The phase diagram posted in another comment shows that the region in which
this particular phase exist is fairly small. Additionally the paper mentions
that they had to add a few trace alloying components to stabilize it in that
phase. I.e. it takes some effort to get to the point.

And even if you can spot a trend by lining up properties of various alloys on
the right diagram, investigating that trend may be out of scope for the
research you're currently doing.

------
taivare
This should eventually be cheaper then gold for jewelry and castable an also
it might be weldable or at least be able to braze ?

------
fosco
Reardon metal!

------
greydius
Finally, someone has found a good use for gold other than ridiculously
overpriced a/v cables.

~~~
kragen
And corrosion-resistant contacts of all kinds, and soft and biocompatible and
corrosion-resistant tooth fillings, and low-resistance conductors (e.g. for
bond wires), and coating glass to get ultra-low-loss mirrors well into the
infrared, and measuring electrical charge in electroscopes, and coloring glass
deep red, and conductive sheets so thin they are transparent, and in anti-
inflammatories for arthritis, and in immunogold labeling, and in making random
things conductive and emit lots of secondary electrons so you can easily look
at them in an electron microscope...

This is why you're being downvoted. Check Wikipedia before commenting next
time.

~~~
greydius
It was meant to be tongue-in-cheek. Gold has some nice useful properties, but
it seems the properties that have mattered most to people throughout the
millenia are 1) it has a pleasing color, and 2) it's hard to come by.

~~~
kragen
Probably more important, it's chemically inert (so it doesn't rust away to
nothing) and it's easy to assay, at least once you can make _aqua regia_ , an
ability which was mastered by the 13th century CE, and possibly by the 14th
century BCE. Harappan touchstones have been recovered, and although
cupellation can't separate gold from silver, it can certainly separate it from
iron, lead, tin, and copper, and we've found cupels with litharge deposits
from the 4th millennium BCE.

Cupellation plus touchstones are adequate both to refine electrum and to
destructively measure the quantity of gold in the electrum. By Roman times, we
were smelting electrum with salt to separate out the gold by chloriding the
silver, and the Lydians may have been doing that already by the fifth century
BCE, when they started debasing their electrum coins with extra silver.

This sounds kind of stupid, since at this point we're used to being able to
purify and quantify all kinds of materials, but in fact these attributes made
gold and silver unique among rare elements for centuries.

~~~
greydius
That's cool! I don't know much about chemistry or metallurgy. I can see a
connection from making gold for real to alchemy to chemistry. So perhaps gold
is partially responsible for creating science? If for no other reason than its
a really good motivator.

~~~
kragen
Absolutely! Although it might also be responsible for the pathetic and
obsessive secrecy that slowed the progress of alchemy.

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mbrumlow
I was a bit frustrated by this title.

~~~
tomrod
I'm always interested in feedback about titles because I feel I do them poorly
(I'm not OP). What do you find frustrating about the title?

~~~
honkhonkpants
Probably that it uses the common definition of toughness an article about
metallurgy while metallurgy has a special definition of that word.

~~~
VLM
Even worse, using real metallurgy words, titanium is really strong per volume
and doesn't care about high heat and is practically corrosion proof and a
couple other weird properties... ironically what its NOT known for is its
rather pedestrian hardness and toughness specs. There's a lot of reasons to
talk up titanium and they carefully sidestepped around each of them LOL in
favor of talking up two things titanium is fairly worthless at (at least
worthless at per dollar or whatever).

If you want something tough that can absorb surprising amounts of energy
without breaking there are exotic nickel steels that require exotic heat
treatment, or maybe some of the military armor plates from the old days
(before HEAT rounds forced other criteria as a figure of merit). Maybe a chunk
of battleship armor plate or maybe the crankshaft from an old diesel ship
engine.

If you want something hard there are some oxidized titanium coatings that are
somewhat hard and industrially useful but nothing unusual or worth writing
home about. Besides that's cheating because its a titanium containing
compound, kinda like saying coal cures scurvy because vit C is merely a
peculiar arrangement of carbon atoms much like coal. Industrial diamonds are
not going to be replaced by titanium rod anytime soon...

~~~
ghaff
It sort of plays to a very simplified layman's understanding of structural
metals as following some sort of uni-dimensional good/better/best scale with
titanium being on the best end of the spectrum. (And, hence, "titanium" being
used in all sorts of product names, such as clothing, which have absolutely to
do with metal except insofar as the production equipment has metal parts--
though probably not many titanium ones.)

