[HN Gopher] New lightweight material is stronger than steel
___________________________________________________________________
New lightweight material is stronger than steel
Author : hhs
Score : 219 points
Date : 2022-02-02 17:33 UTC (5 hours ago)
(HTM) web link (news.mit.edu)
(TXT) w3m dump (news.mit.edu)
| tom-thistime wrote:
| Quick note: this is MIT's PR folks again, not a technical
| article.
| boplicity wrote:
| The most important problem right now that needs to be solved, in
| terms of steel and plastics, is the carbon emissions caused when
| they are manufactured. The manufacture of these materials is one
| of the biggest sources of carbon emissions. I'm curious if this
| new material has the same emissions profile.
| [deleted]
| NiceWayToDoIT wrote:
| How much does it cost to produce? Can we build rocket that will
| go to Mars out of it?
| Melatonic wrote:
| Too bad the article does not actually say what the material is
| made out of. Does this beat UHWMPE? Because UHMWPE is already
| damn strung stuff for its weight. But the big downside being that
| because it is so damn dense it cannot be thermoformed (the big
| plus being that it also has a huge range of temperature
| resistance)
|
| edit:
|
| Correction, it looks like they call it "polyaramide" which sounds
| like it is similar to Aramid like Kevlar. Interesting
| giantg2 wrote:
| Considering the army is one of the research sponsors, it sounds
| like it would be a candidate for a component (backer/trauma
| pad) in body armor.
| throwaway4aday wrote:
| > For the monomer building blocks, they use a compound called
| melamine, which contains a ring of carbon and nitrogen atoms.
| Under the right conditions, these monomers can grow in two
| dimensions, forming disks. These disks stack on top of each
| other, held together by hydrogen bonds between the layers,
| which make the structure very stable and strong.
| prova_modena wrote:
| The article says it is a melamine polymer.
| mrfusion wrote:
| Have they tested this for super conductivity?
| Scene_Cast2 wrote:
| Just a heads up - strength is not a single metric. There is
| tensile (pulling), compression, and shear (sliding) strength.
| There's also Young's modulus (how much something stretches),
| fatigue limits (steel can work perpetually with deformations
| under a certain threshold).
|
| There's also specific strength (strength per kg) vs strength per
| volume and strength per dollar.
|
| Steel also comes in lots of different flavors, with very
| different (orders of magnitude) strengths.
| jimmytucson wrote:
| I've often heard that spider silk is stronger per kg (or is it
| per m^3?) than steel. Are they talking about pulling,
| compressing, sliding, or all of the above?
| lazide wrote:
| Pulling (tensile), which is also the direction steel is
| unusually strong in (from a materials perspective).
|
| Compression wise it's close to a wet noodle the way it's
| manufacturable (though that has more to do with
| cost/practical production/gathering methods - if we could get
| a solid chunk of it I imagine it would be pretty strong in
| compression).
|
| Sliding, it's a fiber, so very weak in that sense (barring
| the same scenario above). It actively flexes, so isn't
| strong'
| ghaff wrote:
| As I recall my material science, it's not so much that
| steel is weak in compression but, if you have a rod of
| steel (i.e. much longer than it is thick), if you compress
| it, it will buckle and shear. As you suggest--I'd have to
| look up the numbers--but a large cube of steel probably has
| similar strength with tensile and compressive loads.
|
| ADDED: In fact, if you deform a supported I-beam you get
| similar amounts of tension and compression on the bottom
| and top respectively at the mid-point of the beam (given a
| variety of assumptions).
| user_7832 wrote:
| > but a large cube of steel probably has similar strength
| with tensile and compressive loads.
|
| Not just similar, but pretty much identical from what I
| recalled from my uni classes. Wikipedia for structural
| materials
| (https://en.wikipedia.org/wiki/Structural_material) also
| has this bit -
|
| >Steel is equally strong in tension and compression.
| ghaff wrote:
| As I wrote in another comment, my material science and
| mechanical engineering is very rusty at this point. :-)
| But, yeah, I-beams basically wouldn't work if steel were
| weak in compression because, assuming a straightforward
| loading of a supported beam you're basically putting one
| flange of the beam in tension and the other flange in the
| equivalent amount of compression. So the fact that one
| part of the I-beam is strong would be pretty much
| irrelevant if the other part were weak.
| Infernal wrote:
| I read the grandparent the same way you did at first. GP
| is talking about spider silk in all three of those
| points.
| TylerE wrote:
| Plenty of things are stronger than steel on a per pound
| basis.
|
| For instance, many aluminum alloys have about 60-80% the
| tensile strength of steel, but only 1/3rd the weight.
| Ma8ee wrote:
| Even wood is supposedly quite much stronger than steel for
| the same weight of material.
| lazide wrote:
| Titanium even more so.
|
| For those, they are actively swapped around where cost vs
| weight trade offs happen.
|
| steel vs aluminum vs magnesium, vs titanium in engineering
| application, where for example engine blocks, airplane
| parts, car parts, battery components, etc. all have a long
| history of this.
|
| It's a complicated process because the trade offs are not
| simple cost/weight/strength.
|
| Steel has an nearly infinite fatigue lifetime for instance,
| so steel springs are great.
|
| Aluminum does not, so aluminum springs are terrible - among
| other things. No amount of weight savings can likely fix
| that problem in a useful way.
|
| These pose big challenges in aircraft in particular where
| aluminum skins and fuselages make flight doable/economic,
| but means pressurized aircraft in particular have a finite
| lifespan in pressurization cycles/takeoffs and landings
| before they fall apart, no matter how nicely you treat
| them.
|
| Several major accidents (including the top of an airliner
| coming off and sucking a flight attendant out over the
| pacific on the way to Hawaii) happened before this was
| fully understood.
|
| Titanium is in theory much better, but is incredibly
| difficult to work with(requiring forgings in most cases,
| and being almost unmachinable), and very expensive as the
| bond it forms with oxygen is so strong the normal fluorine
| based processing used with Aluminum won't work. Yeah, you
| read that right.
|
| Fire danger (such as magnesium engine blocks burning) is
| also a non trivial thing to mitigate. Titanium can be one
| of the worst offenders here (powdered titanium fires can
| burn SAND used to try to put it out as an oxidizer), which
| makes working with it hazardous in some cases. Iron, which
| will also burn, is generally so mellow when it does that
| burning it is a normal operation while scrapping and
| cutting it and you can't get a runaway from doing so except
| in truly difficult to achieve circumstances (it's what an
| oxy-acetylene cutting torch is doing).
| gm3dmo wrote:
| +1 for thorough but:
|
| > Titanium is in theory much better, but is incredibly
| difficult to work with(requiring forgings in most cases,
| and being almost unmachinable), and very expensive as the
| bond it forms with oxygen is so strong the normal
| fluorine based processing used with Aluminum won't work.
| Yeah, you read that right.
|
| I have a spoon bought from Amazon which they claim is
| made from titanium. [Lockheed_SR-71_Blackbird](https://en
| .wikipedia.org/wiki/Lockheed_SR-71_Blackbird) claims 31
| aircraft made from titanium and first flew in 1964. Given
| they got it off the ground in 1964 and can make a spoon
| in 2022 what kind of machining problems are left to solve
| for titanium? Usually it's the other way round like make
| s spoon from wood for 5,000 years then make an aircraft
| in 1905.
| inglor_cz wrote:
| Pressurization cycles is what killed the reputation of
| the first commercial civilian jet, the De Havilland
| Comet.
|
| The British were good in early jet design and actually
| introduced jet aircraft into the non-military world, but
| the early hulls would fail catastrophically after a
| certain, relatively low # of cycles, tearing the fuselage
| apart mid-flight and killing everyone on board. After
| several such incidents in short order, the entire fleet
| was grounded and scientists came up with solutions, but
| by then, the reputation of Comets was tarnished and
| Boeing came with a competing 707 model.
|
| These days, the UK does not have a domestic jet
| manufacturer anymore.
| TylerE wrote:
| That wasn't really a cycles issue exactly, it was they
| used square windows rather than round, leading to stress
| concentrations.
|
| Per your last point, BAE and Hawker are still around. The
| UK also does plenty of Airbus work.
| ghaff wrote:
| >Several major accidents (including the top of an
| airliner coming off and sucking a flight attendant out
| over the pacific on the way to Hawaii)
|
| It was actually an inter-island flight so lots of short
| flights (and therefore pressurization cycles relative to
| flight hours or miles). The amazing thing was that the
| plane was able to make an emergency landing.
|
| https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243
| hutzlibu wrote:
| So this was in 1988?
|
| I would have suspected this story was out of the early
| days of the big airliners.
| albrewer wrote:
| > steel can work perpetually with deformations under a certain
| threshold[*]
|
| [*] Within a temperature range of about ~-30 degC to ~400 degC.
| Below that and the toughness goes way down so that it's prone
| to cracking. Above that and carbon starts to work its way into
| all those crystal structure discontinuities, preventing some
| percentage of the strain from being relieved each stress cycle
| (the "creep range").
|
| That's just for carbon steels. Stainless has a different set of
| problems.
| bungle wrote:
| > Within a temperature range of about ~-30 degC to ~400 degC.
|
| If the new material is plastic-like, it may have worse issues
| here?
| holoduke wrote:
| Exactly. We also have temperature and chemical resistance. Very
| important in most applications and for example an interesting
| discussion between rubber and polyurethane compounds.
| thereddaikon wrote:
| There are also other metrics that are often confused with
| strength but have distinct definitions such as toughness,
| hardness, and wear resistance.
| olliej wrote:
| Yeah I was annoyed about how the article didn't say _what_
| strength they were measuring.
|
| Not of course saying improvement in any of those metrics is
| bad, but the comparison being made needs to say what is being
| compared, and how it compares to the existing best in class.
| SAI_Peregrinus wrote:
| Also those metrics can vary with direction. For steel they're
| usually pretty uniform, but this new substance forms "2D
| sheets" so it's likely strength will be highly directional.
| Maximum tensile and compressive strength are likely to be 90deg
| apart.
| exo-pla-net wrote:
| > The researchers found that the new material's elastic modulus
| -- a measure of how much force it takes to deform a material --
| is between four and six times greater than that of bulletproof
| glass. They also found that its yield strength, or how much
| force it takes to break the material, is twice that of steel,
| even though the material has only about one-sixth the density
| of steel.
| saxonww wrote:
| The problem with this is that steel is a large class of
| alloys, with a wide variety of properties depending on the
| chemical and physical makeup of an alloy. Even "types of
| steel" that people are familiar with - e.g. stainless steel -
| are not specific alloys but themselves classes of alloys. I'm
| not a metallurgist but I assume there are dozens if not
| hundreds of alloys qualifying as steel.
|
| So when someone writes an article saying "it's stronger than
| steel!" that's exciting, but it's not enough information. In
| this case we know it's stronger by yield strength. We can say
| the new material's yield strength is twice that of the
| weakest known steel alloy, but no more than that.
|
| A quick look around found this:
|
| https://amesweb.info/Materials/Steel-Tensile-Yield-
| Strength-...
|
| You can see here, there is a wide gulf between the weakest
| and strongest alloys just in this chart, which only has five
| alloys and a handful of different treatments. Yield strength
| is anywhere from 210MPa to over 1600MPa, an 8x difference.
|
| This page has some charts for the new material:
|
| https://www.researchgate.net/figure/Mechanical-properties-
| of...
|
| Subchart (g) in the image shows a plot of yield strength
| against elastic modulus, and it looks like the plot tops out
| around 1.4 GPa, meaning the strongest tested configuration by
| yield strength is weaker than that of tempered 4140 and 4340
| steels, while nearly 7x stronger than hot-rolled 1020 steel.
| I don't know if "2D yield strength" is different than what is
| shown in the amesweb.info table, though.
| burnished wrote:
| I think you're missing the novel polymer for the steel-
| forest. Its a 2d polymer (spans a plane instead of forming
| strings, which is new) that has material properties that
| make it comparable to materials that we think of as strong.
| The part where it gets rigorously classified can come
| later. The people involved with this project were
| themselves probably not metallurgists.
| TheSpiceIsLife wrote:
| > yield strength, or how much force it takes to break the
| material
|
| That's not yield strength.
|
| Yield strength is how much force is required to permanently
| deform the material.
|
| Ultimate tensile strength is the force required to break the
| material.
|
| One great thing about steels is that they tend to work-
| harden.
|
| Typical 250 grade mild steel, meaning it takes in excess of
| 250 MPa force to permanently stretch a 10mm round diameter
| section, usually has an ultimate tensile strength exceeding
| 400 MPa.
| chainwax wrote:
| I recall hearing similar claims of graphene a while back. I
| realize that the lag time between academic proof-of-concept and
| commercial availability is large, but I still haven't heard of
| any products coming out that are made of graphene. Do these
| materials' use cases overlap?
| soperj wrote:
| I don't think anyone has ever claimed that graphene is easy to
| manufacture.
| chasil wrote:
| I think anybody can make it with adhesive tape and a piece of
| graphite, or so the Nobel prize led me to believe.
|
| Making it in large sizes is more difficult.
|
| https://www.abitape.com/an-unlikely-hero-how-sticky-tape-
| led...
| HPsquared wrote:
| Carbon nanotubes have a similar situation: they're often
| present in soot, but the hard part is to make them in a
| controlled way in large amounts.
|
| https://pubmed.ncbi.nlm.nih.gov/28278030/
| Lio wrote:
| > but I still haven't heard of any products coming out that are
| made of graphene.
|
| Vitoria have sold bike tyres using a graphine layer for a
| couple of years now:
|
| https://www.vittoria.com/ww/en/tyres/road-tires/corsa
|
| They were used by both the winners of the Tour de France and
| Vuelta a Espana last year.
| metal_am wrote:
| Link to the paper: https://arxiv.org/pdf/2103.13925.pdf
| soperj wrote:
| >The researchers have filed for two patents on the process they
| used to generate the material, which they describe in a paper
| appearing today in Nature. MIT postdoc Yuwen Zeng is the lead
| author of the study.
|
| Anyone think they could find the patent that were filed? Or is it
| only once they're approved that you can see them?
| Ballu wrote:
| I think, this is the patent
|
| https://pubchem.ncbi.nlm.nih.gov/patent/US-2021002426-A1
| soperj wrote:
| Wonder if it work as a rebar replacement that doesn't rust.
| throwaway4aday wrote:
| Just coat the rebar, one of its properties is that it's
| impermeable to liquids and gases.
| soperj wrote:
| If it's stronger & lighter than steel and produces less CO2
| than steel manufacturing...
| throwaway4aday wrote:
| Forgot the most important part, is it cheaper than steel?
| Ekaros wrote:
| Also can it be produced at scale we produce steel...
| Which is mind boggling when you really start to think of
| all the stuff.
| r2_pilot wrote:
| That doesn't help if it expands differently from the rebar
| and concrete. One of the advantages of rebar is that it has a
| similar coefficient of thermal expansion so when there are
| temperature changes the concrete and rebar expand and
| contract in sync and don't have stresses from that.
| [deleted]
| rini17 wrote:
| Depends on thermal expansion coefficient.
|
| If the solution chemistry is compatible with concrete then it
| might be mixed in and polymerize together, and that would be
| yet more exciting.
| blix wrote:
| Probably not. Steel rebar is used because it is ductile, that
| is it stretches and fails gracefully, which complements the
| brittle nature of concrete.
|
| This material is likely brittle, probably similar in overall
| behavior to graphite.
| montjoy wrote:
| > and can be easily manufactured in large quantities
|
| That seems promising.
|
| I have a couple of concerns - Can it be recycled? - How are new
| materials like this tested for toxicity?
| omegaworks wrote:
| The article mentions that it's melamine, which we currently
| find in Magic Erasers. It isn't recyclable or biodegradable,
| but seems to be non-toxic enough to be a regular fixture in the
| household cleaning arsenal.
|
| It would be far better to use it as (long-lived) building
| material than as a sponge that quickly degrades and gets rinsed
| down the drain.
|
| 1. https://livegreen.recyclebank.com/column/because-you-
| asked/w...
| loceng wrote:
| Isn't the tradition that something reaches mass market before
| whatever suppression and disinformation campaigns, paid for by
| the industry, before there's a strong enough response and
| therefore reaction by elected officials - who otherwise don't
| pay attention to such issues? Hopefully it's not harmful/toxic,
| but we don't seem to have an apparatus that counters the above
| influence; sugar, cigarettes, asbestos, etc.
| mgas wrote:
| I agree with concerns about recyclability. I would also raise
| concerns about the renewability and/or toxicity of the base
| materials. If they are petroleum-based, this feels like a
| losing proposition.
| adrian_b wrote:
| Unfortunately the recyclability and the lack of toxicity are
| contradictory, they cannot be satisfied simultaneously for
| this kind of materials.
|
| As long as the 2-dimensional polymeric sheets do not
| decompose, they will not be toxic, as they cannot enter a
| living cell (in the form of fine dust they could cause the
| same problems as any mineral dust, e.g. respiratory damage
| through purely mechanical action).
|
| However if they do not decompose, they can be recycled only
| by burning.
|
| If they can be decomposed into monomers by heat, light or
| chemicals, then the monomer can be recycled. However in that
| case some spontaneous decomposition will also occur in old
| objects made of the 2-dimensional polymer and the released
| monomer molecules would cause toxicity problems.
|
| So only one of these 2 features must be chosen and optimized.
| hgomersall wrote:
| Plastics can be toxic by leaching additives without the
| polymer itself breaking down. Moreover, much of the damage
| caused by microplastics (i.e. only mechanically broken
| down) is poorly understood. At the very least, they seem to
| harbour novel collections of microbes that aren't
| necessarily benign.
| adrian_b wrote:
| It is quite certain that a 2-dimensional polymer cannot be
| recycled like metal, glass or a thermoplastic material, i.e. by
| remelting or by plastic deformation at high temperatures,
| because a 2-dimensional polymer cannot be deformed without
| breaking covalent bonds and it cannot flow in a liquid state.
|
| So this new material might behave like the existing cured
| polymeric resins, e.g. epoxy resins, which form a 3-dimensional
| network of covalent bonds after curing, so they cannot be
| melted, and which when heated decompose before melting. Such
| materials can usually be recycled only by burning.
|
| Nonetheless, there might be a more complex way to recycle the
| new materials, if the new materials would decompose in monomer
| molecules when heated or if there would exist some solvent able
| to break the bonds between monomer molecules, transforming the
| solid 2-dimensional polymer into a solution of the monomer
| molecules.
|
| If such a method to depolymerize the 2-dimensional polymer
| would exist, the obtained monomer could be reused to synthesize
| again 2-dimensional polymers.
|
| If the depolymerization is impossible then these materials
| would be used in the same way like the already existing and
| widely used insoluble and infusible polymeric resins.
|
| More important for their success is what processing methods
| will be applicable for them. After the 2-dimensional sheets are
| formed, they cannot be processed by any of the popular methods,
| e.g. injection in a mold. The thermoset polymers behave
| similarly after curing, but they are produced in a state where
| they are only partially polymerized in 1-dimensional molecules,
| so they can be molded in the final shape and the complete
| polymerization happens later.
|
| For now, it seems that these new 2-dimensional polymers can be
| made only as sheets, and then you must cut them in the shapes
| that you need, which will waste material in comparison with
| making the same shape from a thermoplastic or thermoset
| material.
|
| Another problem not mentioned is that of the fracture
| toughness. They have made some tensile strength measurements
| and there is no doubt that the 2-dimensional polymers will have
| outstanding tensile strength. However the problem is which will
| be their fracture toughness for bending. Graphite has a similar
| structure and it also has excellent tensile strength in the
| direction parallel with the sheets, but it is also extremely
| fragile when you bend it.
|
| An advantage of the 1-dimensional polymers is that they, like
| metals, can be deformed without breaking covalent bonds, which
| results in high fracture toughness for metals and 1-dimensional
| polymers, unlike the substances with 2-dimensional networks of
| covalent bonds (e.g. graphite) or 3-dimensional networks of
| covalent bonds (e.g. diamond), which are fragile.
|
| So more research is needed to determine how useful these
| 2-dimensional polymers can really be.
|
| In any case, just achieving their synthesis is already a very
| impressive result.
| cellis wrote:
| Your answer illustrates why, after all these years, HN is
| still one of the best places to lurk. As someone who forgot
| most of what he learned in HS chemistry, and didn't take any
| collegiate courses, what material would you recommend to
| learn about this stuff?
| adrian_b wrote:
| I am sorry but I cannot give a good recommendation as some
| years have passed since I have last searched for chemistry
| books in this domain.
|
| If you go to Amazon and you search, e.g., for "Polymer
| Chemistry" and for "Materials Chemistry", you will find
| much more than 100 books. However I do not know which are
| the best among the recent books.
|
| A less risky way than ordering such a book, and finding
| after paying for it that it is a dud, would be to go to an
| online site like Library Genesis, search there for such
| books (there are plenty), browse through them and maybe, if
| you find what you need, choose one or more to buy in
| printed form.
|
| Alternatively, you can read the Amazon reviews for such
| books, to determine which would be worthy. The Amazon
| reviews for such specialized items as a science book are
| usually more trustworthy than for items of general
| interest.
| user_7832 wrote:
| Not the person you're replying to but William D Callister's
| Material Science and Engineering is a pretty standard
| engineering book I've seen used in my different
| universities across 2 continents (and have studied from
| too), so I'm going to say that it's a good starting point.
| webmaven wrote:
| You seem to be assuming that the 2D polymers extend
| indefinitely. If instead their growth is limited such that
| the molecules tile, overlap, and layer, they may be more
| amenable to manipulation such as thermoforming,
| thermosetting, etc.
| adrian_b wrote:
| The paper claims that they have obtained 2D sheets of very
| large extent, not small flakes that can overlap.
|
| The advantages that they claim over conventional polymers,
| e.g. inpermeability and high tensile strength, are
| conditioned by such large extents. If the 2D sheets would
| be small enough to slide over each other and insert between
| other sheet fragments, so that plastic deformation would be
| possible, then they would also lose any advantages over
| traditional polymers.
| SideburnsOfDoom wrote:
| > a couple of concerns - Can it be recycled?
|
| Right. We have enough issues with plastic waste, without it
| having extra-ordinary strength.
| cooljacob204 wrote:
| Also steel is 100% recyclable. If I recall correctly, most
| steel used today is recycled.
| dzhiurgis wrote:
| If this has 100x less carbon footprint and steel is 90%
| recycled, the polymer still wins overall.
| missedthecue wrote:
| Most steel in the US and Europe is recycled. I believe most
| steel in China and to a larger extent Asia comes out of a
| giant pit in Australia.
|
| https://en.wikipedia.org/wiki/Yandicoogina_mine
| javajosh wrote:
| That mine runs fully automated ore trucks and the owner
| Rio Tinto wants to automate the rest. 950 ppl produce 18%
| of the world's iron ore from that pit.
|
| https://www.abc.net.au/news/2015-10-18/rio-tinto-opens-
| world...
| giantg2 wrote:
| It's possible the strength could reduce microplastics?
| catskul2 wrote:
| I imagine that even things that are nominally strong might
| be susceptible to things like UV. But IANAC.
| adbachman wrote:
| Or increase the risk posed by microplastics.
|
| Very tiny, very sharp flakes of very strong materials could
| be asbestos 2.0
| ngngngng wrote:
| The article touches on potential to use instead of steel, perhaps
| even in buildings. But I imagine its heat tolerance would likely
| kill any chances of that, no?
| throwaway4aday wrote:
| It's potentially a thermoset plastic in which case it should be
| able to resist somewhat high temperatures (maybe 300C). So not
| fireproof but not terrible either.
| cbg0 wrote:
| As a comparison, various types of insulation are rated for
| 60/90 minutes at 1000 degrees Celsius, while some types of
| brick are rated for 180 minutes. If this material can't
| sustain similar temperatures, it's unlikely it will be used
| in construction.
| gm3dmo wrote:
| Because, when it is used in construction:
|
| https://en.wikipedia.org/wiki/Grenfell_Tower_fire
| ngngngng wrote:
| Can I ask how you know these things? Materials science is
| pretty far outside my area of expertise but I'd love to get
| a basic understanding of it.
| cbg0 wrote:
| There are a bunch of standards for material fire
| classification, which may differ from country to country,
| but they're not really available to read online for free
| most of the time. You can do some googling around A1 fire
| classes, EI fire rating and so on.
|
| A useful thing to know is that a house fire revolves
| around 800 degrees Celsius typically, so you should
| expect various materials that have a fire resistance
| rating to take more than that for a sustained period.
| AnimalMuppet wrote:
| Wait, what happens to brick after 180 minutes at 1000
| Celsius? I assumed they would either burn or not burn, melt
| or not melt.
| cbg0 wrote:
| It's just one standard, it doesn't mean anything happens
| to the brick, they probably just stopped testing at that
| point.
| tagoregrtst wrote:
| I hate title.
|
| Do they mean run of the mill plastic?
|
| What does stronger than steel mean? Tensile strength? Yield
| strength? Toughness?
|
| And "stronger" than steel is not that impressive in of itself.
| Many materials are stringer than steel. Steel's combination of
| properties makes it useful, not merely its tensile strength.
| smm11 wrote:
| Tougher than diamonds and stronger than steel?
| sandworm101 wrote:
| Are there any samples big enough to be seen without a microscope?
| After a decade or more reading about nanotubes and graphene I'm a
| little jaded about "easily manufactured in large quantities". How
| long does it take to create a solid 1-foot cube? If you are
| comparing a new material to steel or concrete "large quantities"
| means multiple tons per hour. I'm going to need to see a sample
| bigger than a doorstop.
| cousin_it wrote:
| Maybe a stupid thought, but could a carbon-based building
| material be the best possible news for carbon sequestration? I
| mean, we humans need a lot of buildings.
| atrus wrote:
| I'd argue that most of our building in North America are built
| from carbon based materials, wood.
| gloriana wrote:
| interesting research and not sure what to make of it. But did
| stumble on a more comical discovery by these MIT professors -
| heated covid masks lol : https://news.mit.edu/2020/heated-face-
| mask-coronaviruses-102...
| arendtio wrote:
| And we thought spaceships would be built out of transparent
| aluminum ;-)
| thedatamonger wrote:
| Herbert was a prophet. https://dune.fandom.com/wiki/Plasteel
| Bancakes wrote:
| Sometimes you want steel because it's dense and rugged - it can
| physically withstand damage and last longer. As in steel engines
| versus titanium ones.
| californiasurf wrote:
| This material should produce some interesting surfboard designs
| throwaway4aday wrote:
| Can't wait for 3D printed parts made out of this stuff.
|
| > the new material's elastic modulus -- a measure of how much
| force it takes to deform a material -- is between four and six
| times greater than that of bulletproof glass. They also found
| that its yield strength, or how much force it takes to break the
| material, is twice that of steel, even though the material has
| only about one-sixth the density of steel.
|
| That's going to make for some fun prints.
|
| Edit: density of steel is 7.85 g/cm3 and 1/6 of that is 1.3 which
| makes it less dense than wood! (1.5 g/cm3) It floats!
| blix wrote:
| It's hard to say without reading the paper itself, but in
| general one should be skeptical of claims that such-and-such
| material is stronger than steel. The properties that make steel
| interesting are not its elastic modulus or yield strength.
|
| This material is probably closer to graphite (which beats steel
| in elastic modulus and yeild strength) than something you would
| actually want to use in a structural application. It will
| probably be ~very~ difficult to print.
| sdmike1 wrote:
| I'm curious, in that case what properties _do_ make steel
| interesting?
| kragen wrote:
| Well, its elastic modulus and yield strength are pretty
| important, actually. Being stiff and strong is pretty
| fundamental to a lot of its uses. It's stiffer and stronger
| than most other everyday materials and virtually all
| everyday _plastic_ materials. Glass, quartz, alumina,
| zirconia, and porcelain are stiffer than steel, and glass
| can be stronger, but they 're all brittle rather than
| plastic, which is pretty inconvenient and often makes them
| very weak in tension. Wood, most other fired clay,
| aluminum, brass, nearly all organic polymers, mica, cotton,
| dirt, etc., are much floppier and weaker than steel.
|
| But there are a lot of metals that are somewhat stiffer and
| stronger than steel, like chromium, platinum, and tungsten,
| while still being somewhat plastic. The great advantage
| that steel has over them is that it's _unbelievably cheap_.
| It 's even cheaper than brass, bronze, and lead!
|
| Plasticity (ductility and malleability) is important for a
| couple of reasons. First, as I mentioned above, it greatly
| increases the fraction of the material's theoretical
| strength you can get in practice. Second, it allows you to
| _form_ the material instead of cutting it to shape. That 's
| the property you're using when you wrap a sandwich in
| aluminum foil or tie a gate shut with baling wire. You
| can't do that with porcelain foil or porcelain rod. Third,
| ductile failure happens gradually rather than suddenly,
| which is important in some cases.
|
| The other really interesting thing about steel is that it's
| _hardenable_. This is very significant because cutting and
| forming hard things is hard. So it 's routine to cut or
| form steel in its soft state to get more or less the shape
| you want, harden it, and then grind it and maybe lap it to
| the precise shape you want. Grinding and especially lapping
| can be very precise and cut very hard materials, but
| they're very slow processes.
|
| Finally, steel can withstand _much higher temperatures_
| than organic materials, or even most other common metals.
|
| These are, I think, the major reason why steel has so
| extensively displaced what Andrew Carnegie liked to call
| "inferior materials".
| blix wrote:
| The two main properties that make steel interesting are 1)
| cost 2) toughness.
|
| Toughness in a material science sense is the ability to
| absorb energy before failure. This has two major
| components, yield strength (energy to initiate deformation)
| and ductility (ability to deform without fracture).
|
| The ductility of steel (and of many other metals) is what
| drive their use in structural applications, whereas many
| materials, i.e. ceramics, have higher yield strength but
| almost no ductility. Even though many glasses are "stronger
| than steel", if you drop a glass bowl and a steel bowl only
| one will shatter. If your I-beam shatters you are in
| trouble.
|
| Steel is interesting in comparison to other metals because
| iron and carbon are abundant and the iron-carbon system has
| a lot of interesting features that can increase both
| strength and ductility.
| the_cat_kittles wrote:
| another great plus is its weldable
| ummonk wrote:
| It's really tough (i.e. not just strong but ductile as well
| i.e. able to stretch more without fracturing like a brittle
| material would) and relatively cheap to manufacture (both
| because the industrial process is scalable, and because
| iron is incredibly abundant). When cost isn't an issue, you
| don't use normal low alloy steel - you use expensive
| alloying elements like chromium for corrosion-resistant
| stainless steel or more relevant to this comparison, nickel
| for maraging steel which is several times as strong as
| ordinary steel.
| Rury wrote:
| Some great answers here, but one other thing to add, is
| that it's also a material that's quite easy to recycle.
| rdiddly wrote:
| Mainly it's the ability to absorb energy and punishment.
| Many materials have an elastic range, where if you deform
| it within that range, it will return to its original shape.
| Of those, a lot of materials, including many metals, are
| relatively brittle - once you push it past its "elastic
| limit" it just breaks. There are ways to make steel more
| like that too, but in general steel doesn't break at that
| point, it "yields" or deforms permanently (inelastically).
| You can keep on deforming it (and in fact it actually gets
| slightly _stronger_ while you 're doing that, which is an
| interesting feature) and it goes way way beyond what you
| would think possible before it finally breaks. So as a
| result it can absorb tons of energy, which makes it
| interesting for strength applications. The steel frame of a
| building in an earthquake for 30 seconds is absorbing tons
| of energy while hopefully not collapsing, or even in the
| worst case it at least allows a bunch of extra time for at
| least some of the occupants to escape. Or a steel-framed
| car that crashes into a pole - the steel crumples, absorbs
| energy, and slows the car somewhat more gradually in the
| process. If the frame were a brittle material it might just
| shatter on impact.
| metal_am wrote:
| It's dirt cheap and incredible versatile. It has many
| different crystal structures that can give you an
| incredibly wide range of properties. General purpose mild
| steel used in buildings. Stainless steel that resists
| corrosion. Maraging steels used in aerospace.
|
| Also, the high modulus is interesting. Some components are
| stiffness limited such that you couldn't use aluminum or
| titanium even if you wanted.
| robbedpeter wrote:
| It's a thermoset plastic - melamine - and not very suitable for
| either resin or thermoplastic printing. It looks like polarized
| light is part of the polymerization process, to get 3d
| linkages, so even if you could print, you'd only get super
| strong layers, not necessarily strong overall prints.
| woeirua wrote:
| It always amazes me at how many people don't really understand
| how buoyancy works.
| ummonk wrote:
| I mean, if you stuck it in a puddle of liquified hardwood,
| maybe it would float.
| cypherpunks01 wrote:
| "When disagreeing, please reply to the argument instead of
| calling names."
| loeg wrote:
| How does this compare with carbon fiber-epoxy laminate for
| elastic modulus? I don't have a ballpark figure for bulletproof
| glass. Looks like a typical carbon fiber laminate has similar,
| if slightly higher density (around 1.5 g/cm3).
| [deleted]
| gp wrote:
| It would still sink as water has a density of 1, depending. I
| think your lookup for wood's density gave you a number
| belonging to a hardwood.
| throwaway4aday wrote:
| You're right, but it is close. Add some air bubbles and it
| would be buoyant.
| HPsquared wrote:
| I mean technically a submarine is just a bunch of steel and
| one big air bubble.
| throwaway4aday wrote:
| It's all about the size of the air bubble.
| 0xbadcafebee wrote:
| What happens when it catches fire?
| kazinator wrote:
| Lots of _old_ lightweight materials show tensile strength greater
| than steel.
|
| For instance, oh, nylon fiber is stronger than some steels, and
| way less dense:
|
| https://en.wikipedia.org/wiki/Ultimate_tensile_strength#Typi...
|
| One kind of steel, "ASTM steel" comes in at 400-500 MPa; nylon
| fibers at 900.
|
| Check out the Bamboo entry in the table. Human hair is also
| impressive.
| riskable wrote:
| I can't believe no one has mentioned this: The researchers claim
| this material is _completely impervious to gasses_. Does that
| mean we 've finally got a way to store hydrogen without having it
| constantly leaking away?
| kardos wrote:
| And is that strength enough to put vacuum airships back on the
| menu?
| solarmist wrote:
| I'm intrigued. What's a vacuum airship?
| kardos wrote:
| https://en.m.wikipedia.org/wiki/Vacuum_airship
|
| Like a blimp but with a rigid balloon filled (ha ha) with
| vacuum instead of a light gas.
|
| The article is saying it's a polymer so I'm guessing it
| doesn't have the right rigidity, ie, the stronger than
| steel bit must be with respect to a different strength
| measure
| solarmist wrote:
| ....wow, that is the most counter-intuitive idea I've
| seen in a long time!
|
| A helium balloon makes sense, it's lighter than air so it
| floats, duh.
|
| Well, what's lighter than that? Nothing (vacuum)! It's
| such a dumb, but correct answer that I had a hard time
| wrapping my head around it.
|
| Yup, theoretically a vacuum would be extremely buoyant if
| we could put it in a light enough structure.
| adrian_b wrote:
| It is impervious to gases in comparison with the 1-dimensional
| polymers, which have large inter-molecular spaces through which
| small molecules can pass.
|
| There is no reason to believe that these 2-dimensional polymers
| are more impervious to gases than metals or glasses or covalent
| or ionic crystals, all of which have similar inter-atomic
| distances.
| tomrod wrote:
| Any time I see one of these numerous claims, I apply the
| following question set:
|
| [1] What are the other metrics to consider? Compression, shear,
| tensile, and so on (another comment mentions this)
|
| [2] What are the expected production costs?
|
| [3] Are the costs internalized for production? (I.e. no more
| teflon ecodisasters)
|
| [4] Where should it be used?
|
| "Anything" can be "stronger" than "steel" -- it matters what the
| use cases are. Lasers are great to send signals, but we don't
| want to establish worldwide mesh protocols with it
| servytor wrote:
| Yay, Rearden Steel!
| mikeyouse wrote:
| Actual journal article from Nature ( _Edit: requires sub, look
| one comment below for an ungated version_ ):
| https://www.nature.com/articles/s41586-021-04296-3
|
| (Not on SciHub yet but the figures provide some useful info)
| blix wrote:
| Nature is asking for a subscription, so here's a version on
| arxiv: https://arxiv.org/ftp/arxiv/papers/2103/2103.13925.pdf
| girafffe_i wrote:
| NAR8789 wrote:
| > Such a material could be used as a lightweight, durable coating
| for car parts or cell phones, or as a building material for
| bridges or other structures, says Michael Strano, the Carbon P.
| Dubbs Professor of Chemical Engineering at MIT and the senior
| author of the new study.
|
| Anyone else get immediately sidetracked by how metal the name
| "Carbon P. Dubbs" is? (and how unexpectedly apropos it is to
| chemical engineering?)
|
| https://digging-history.com/2016/01/18/tombstone-tuesday-car...
|
| Apparently his full name was "Carbon _Petroleum_ Dubbs " and the
| relation to chemical engineering isn't really coincidental.
| [deleted]
| zwieback wrote:
| Hmm, here it says 2D polymers were created first at ETH in 2012:
|
| https://scitechdaily.com/two-dimensional-polymers-created-fo...
|
| Either way, looking forward to buying this stuff cheap and in
| bulk from McMaster!
| jdonaldson wrote:
| Probably will be a go-to for fixing up old buildings and
| failing bridges. We always can use more tools there.
|
| On the other hand, I wonder what kinds of hoops one has to jump
| through to demolish/recycle this material.
| solarmist wrote:
| I agree with a lot of the commenters here. This is a meaningless
| headline.
|
| The essential quality of the metal is its being rigid with the
| ability to deform without fracturing, so talking about its
| strength is useless. There are tons of things that are stronger
| than steel already. Still, they don't also have the property of
| deforming without destruction or, on the opposite, holding its
| form rigidly while maintaining its strength.
| sirtimbly wrote:
| Pressure vessels. Big ones.
| joseph8th wrote:
| Ok I'll ask the question:
|
| Will it fill the oceans with indestructible junk?
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