8 ms·
'Metallic wood' has the strength of titanium and the density of water
- michaelbuckbee 8y agoInteresting, seems like nanoscale metal foam: https://en.wikipedia.org/wiki/Metal_foam https://en.wikipedia.org/wiki/Metal_foam
- Isamu 8y agoI guess so called because "woody metal" sounds weird? >"The reason we call it metallic wood is not just its density, which is about that of wood, but its cellular nature," Pikul says. "Cellular materials are porous; if you look at wood grain, that's what you're seeing? -- parts that are thick and dense and made to hold the structure, and parts that are porous and made to support biological functions, like transport to and from cells."
- ph0rque 8y agoI wonder if one could 3D-print such structures?
- cordite 8y agoThe particulates that process might make would be a problem of its own
- egypturnash 8y ago"The struts in the researchers' metallic wood are around 10 nanometers wide, or about 100 nickel atoms across. Other approaches involve using 3D-printing-like techniques to make nanoscale scaffoldings with hundred-nanometer precision, but the slow and painstaking process is hard to scale to useful sizes." - TFA
- jarfil 8y agoYou can 3D print similar structures at a much larger scale. Some of the benefits are retained, like a better overall resistance to weight ratio, some others are not, like increased resistance to localized damage. It's pretty much what different kinds of infill do in 3D prints, which let you control the degree of resistance/deformation of a part in different axes while keeping a low weight.
- jandrese 8y agoThe article was big on having them self-assemble, which is probably the only practical way to build large quantities of nanoscale materials. Downside of course is controlling for defects.
- ohiovr 8y agoWhat kind of strength? Every aspect? Super. If it doesn’t have the stiffness of titanium it isn’t really as strong. Edit ok sorry that I confused stiffness with strength. Sorry my lay opinion was factually incorrect If it turns out to be brittle it can’t be used in the wings. That is my lay opinion on making an aircraft.
- lenticular 8y agoStiffness is usually not considered strength. Strength, whether in compression, tension, or shear, is usually defined as the load it can handle without plastic deformation or fracture. Elastic deformation is by definition reversible once the load is removed. Titanium actually isn't that stiff, either. It's quite a bit more flexible than steel. New martensitic steel alloys can be close to a match for the best titanium alloys for strength/weight ratio as well. Since this material is less dense, it should provide better stiffness for weight, since thicker members can be constructed with the same weight. Much like how aluminum bicycles have much larger tubes than steel ones, to make up for the greater elastic flexibility of aluminum.
- RobertoG 8y agoIt would be interesting to know why they choose nickel.
- skykooler 8y agoEasy to electroplate with?
- MrLeap 8y agoNickel tends to be corrosion resistant. Oxidation is a probabilistic sort of thing. The higher the surface area, the higher chance of corrosive cascades. A metal sponge has significantly higher surface area than the equivalent mass of polished bar stock. I bet if they did the same thing with iron, a drop of peracetic acid on it would make it go "FOOF!". Actually that might still work on the nickel.
- zafka 8y agoelectro-less nickel plating has been around for years. You dust your object with a catalyst- often palladium and you can coat just about anything with nickel
- dschuetz 8y agoThe fact alone that it's lighter than titanium is a big deal. That's great. But, too bad that nickel is toxic as hell, and many people are allergic to it. So, I guess it's the biggest trade-off when compared to titanium.
- IshKebab 8y ago"Some people have an allergic reaction to it" is hardly "toxic as hell".
- Finnucane 8y agoI think we can put nickel in the "do not eat" category: https://rais.ornl.gov/tox/profiles/nickel_and_nickel_compounds_f_V1.html https://rais.ornl.gov/tox/profiles/nickel_and_nickel_compoun...
- jessaustin 8y agoYes, in that sense it is worse than e.g. iron. One can still imagine applications that don't carry a high risk of ingestion or inhalation.
- dschuetz 8y agoIt's both, toxic and an allergen.
- Kalium 8y agoYou're right! Let me see if I can clarify the original point. Nickel is both toxic when ingested and often a contact allergen. Thus the two points are independently true of one another and in no way contradictory. I hope this has been helpful.
- njarboe 8y agoWhat generally happens to kids that find a US nickel on the ground/floor and swallow it without their parents notice? This must have happened a million of times.
- keepper 8y agoLignumified metal? :) ( lignum is wood/timber in Latin )
- droopyEyelids 8y agoWhat kind of world do we live in where Sciencedaily.com uses phrases like "titanium, which is as strong as steel but about twice as light" Twice as light.
- okl 8y agoAlso: "strong as steel" - which measure of strength and which sort of steel?
- thfuran 8y agoFine, it weighs two times less.
- someone454 8y agoIt’s half the mass ;)
- marcosdumay 8y agoIt's confusing. I can as easily conclude it's either 1/2 or 1/3 of the mass.
- thfuran 8y agoOr we could have finally managed negative mass.
- MarsAscendant 8y agoI suspect it has to do with connotations. When you hear "heavy" as used to describe something, you automatically assume it to mean negative. "Half is heavy" has a more negative connotative meaning than "Twice as light", even though they have the same denotative meaning. In other words, they effectively mean the same thing, but represent that thing differently. I also suspect it has to do with the positive/negative framing. Ideally, you want to leave a positive impression on your audience. If you're talking about scientific discoveries – especially something as cool as a material that's comparable to titanium in terms of strength, yet is much lighter – I reckon you want your audience to feel excited and inspired. In this case, using positive framing is reasonable and conducive to the goal. I'm not sure how appropriate it is for a popular-science publication to refer to framing when talking about new discoveries, and am not offering support for or against such usage in this context. The decision to put the phrase in such a way, however, may well be an informed choice that makes sense from the perspective of the goal of such a publication.
- deleted 8y ago[deleted]
- logfromblammo 8y agoThe problem with metamaterials that have interesting macro-scale properties has always been manufacturing them cost-effectively and in quantity. It hardly matters if this stuff has a better strength-to-weight ratio than titanium if it also costs 1000 times as much to make an airplane wing out of it. "Metallic wood" is a very misleading term, too. The material in question is nickel with a cellularized structure resembling wood, rather than a cellulose variant that has undergone some process that bestowed metal-like properties upon it. A more accurate term would have been "xyloid metal" or "ligneous metal".
- jandrese 8y agoPlus other factors like the failure modes or how it fatigues in use or how badly it is affected by corrosion or unfortunate thermal constraints. There are plenty of super light and strong but materials that are not suited for use in vehicles or large structures due to a practical limitation of the substance. Nobody wants to build an airliner wing that is 70% of the weight of a regular wing, but also explodes into a million tiny pieces when it suffers a bird strike.
- MrLeap 8y agoNickel tends to be very corrosion resistant. Though these properties are probably diminished by the increased surface area of the porous topology. I run a small forge. Every alloy I've used will corrode way faster if it's not been finished smooth. I can only imagine how fast a metal (even nickel) foam oxidizes.