Anyone remember some of the new materials created recently?

[Darvil]

I was wondering if anyone remember some of the really cool new materials being created. Last I remember was a new metal created by an Isreali company that is suppose to be extremely hard but I can't recall where I got it from. There was also this one other material that they're making from spider silk.

Anyone know other new stuff that are created already? I would really appreciate it if someone can direct me to some links.

Thanks!

 

[CycloWizard]

There are new materials coming out all the time. The single biggest source is probably the Air Force Research Lab's Materials and Manufacturing Directorate. Check this link for specific cases that have been released to the public. I used to work in AFRL/MLB, but have been elsewhere for the last 3.5 years or so. MLB (non-metallic materials) and MLL (metallic materials/ceramics) are the ones you'll want to sift through.

 

[Bladen]

Wasn't it some kind of metallic alloy that was super cooled to form the crystal structure some fancy way.

They said they have to find suitable alloy mixes that allow for this to happen, the only one thus fr was like >50% platinum IIRC.

 

[CycloWizard]

Originally posted by: Bladen
Wasn't it some kind of metallic alloy that was super cooled to form the crystal structure some fancy way.

They said they have to find suitable alloy mixes that allow for this to happen, the only one thus fr was like >50% platinum IIRC.

There are literally infinite crystalline structures that you can form by cooling metals in different ways. The most cutting-edge thing that I know of are superalloys being developed for light-weight, super-hard properties. They typically involve some alloy of aluminum, titanium, nickel, and possibly some other materials. The process by which these metals are made/cast largely determines the properties of the resulting material. I could mix a 5% nickel/95% titanium alloy and cool it two different ways and have completely different properties because the crystalline structures would be completely different. One of my old roommates still works for the AFRL and he tells me that they typically try to correlate grain size (some characteristic length of one phase of the metal) with the mechanical properties.

Here is a link that I found with a quick search discussing metal phases and how you might form one over the other.

 

[Mday]

there are various materials that are constantly being worked on:
polymer (plastics), ceramic and metal. Then there are mixtures of the 3 - composites.

one of the fronteers is nano machines.

then there are always the crazy things going on in the electronic world.

 

[Gibsons]

Originally posted by: CycloWizard
There are new materials coming out all the time. The single biggest source is probably the Air Force Research Lab's Materials and Manufacturing Directorate. Check this link for specific cases that have been released to the public. I used to work in AFRL/MLB, but have been elsewhere for the last 3.5 years or so. MLB (non-metallic materials) and MLL (metallic materials/ceramics) are the ones you'll want to sift through.

Thanks for the link.

Could you expand a little on the non-crystalline alloys?
link

I've read about them before and they always seem to be hyped as a super-material, but are hard to make, and can currently only be made in thin sections. Aside from production difficulties, what are the material "downsides" (if any?) to them as compared to crystalline alloys? in other words, I've read some marketing hype that touts how they are superior to normal alloys, but I'm assuming they can't outperform them in every category.

 

[CycloWizard]

Originally posted by: Gibsons
Thanks for the link.

Could you expand a little on the non-crystalline alloys?
link

I've read about them before and they always seem to be hyped as a super-material, but are hard to make, and can currently only be made in thin sections. Aside from production difficulties, what are the material "downsides" (if any?) to them as compared to crystalline alloys? in other words, I've read some marketing hype that touts how they are superior to normal alloys, but I'm assuming they can't outperform them in every category.

I have to admit that I'm not an expert on this by any stretch (and I know literally nothing about ceramics), but I can try. If you can come up with some specific questions, I'll fire out an e-mail to my old roommate who works on that team to see if he can shed any light for us as well.

Basically, traditional minimally-crystalline metals are formed by equilibrium (or 'infinitely slow') cooling. This is because crystal formation in metals is the result of more rapid cooling that freezes microstructures in place. This means that, to form a truly amorphous metal, you would have to heat the metal up VERY hot to where only one homogeneous liquid phase exists, then freeze it in the same form it has as a molten liquid. This probably involves casting into some mold that is cooled via convection with fast-flowing liquid nitrogen (or similar).

The crystals in crystalline metals represent one solid phase, while the rest would be considered 'solvent' atoms - the bulk phase - that surround these crystals. In these crystalline metals, failure generally occurs at the phase transition between crystals and the bulk phase. Thus, the phase transitions really control the mechanical properties of the solid, since these properties are flaw-driven. Thus, by removing such 'flaws' altogether, the material would become very strong.

Looking at the link you provided, it says that the metallic glasses must be cooled at 1000°C/second, which tells me that they can only produce thin plates at this time because of heat transfer limitations. A thin slab has very good heat transfer characteristics, since it has a very large surface area per volume. When you make the slab thicker, conduction within the slab becomes the limiting step in heat transfer.

I'm not sure what effect the crystalline structure has on the thermal conductivity of metals, but perhaps removing it decreases this property. I would actually anticipate the opposite, because heat is transferred in metals by the easy passing of electrons from one atom to the next, taking its kinetic energy (which is a result of the atom's internal energy, proportional to temperature) along to the next atom. Thus, the more ordered the structure and tighter the packing, the higher the thermal conductivity should be. Thus, perhaps even a very high thermal conductivity does not allow these rapid cooling rates when the thickness of the sample exceeds a certain amount. If I'm right and amorphous metals have a higher thermal conductivity, then there's not much that can be done about having only thin samples (except if very complex processes were developed). If I'm wrong and amorphous metals have lower thermal conductivity, it may be that doping with some other material may increase the thermal conductivity and allow thicker plates to be cast, though there would necessarily be some decrease in the material properties as a result.

 

[Gibsons]

Originally posted by: CycloWizard

Originally posted by: Gibsons
Thanks for the link.

Could you expand a little on the non-crystalline alloys?
link

I've read about them before and they always seem to be hyped as a super-material, but are hard to make, and can currently only be made in thin sections. Aside from production difficulties, what are the material "downsides" (if any?) to them as compared to crystalline alloys? in other words, I've read some marketing hype that touts how they are superior to normal alloys, but I'm assuming they can't outperform them in every category.

I have to admit that I'm not an expert on this by any stretch (and I know literally nothing about ceramics), but I can try. If you can come up with some specific questions, I'll fire out an e-mail to my old roommate who works on that team to see if he can shed any light for us as well.

Basically, traditional minimally-crystalline metals are formed by equilibrium (or 'infinitely slow') cooling. This is because crystal formation in metals is the result of more rapid cooling that freezes microstructures in place. This means that, to form a truly amorphous metal, you would have to heat the metal up VERY hot to where only one homogeneous liquid phase exists, then freeze it in the same form it has as a molten liquid. This probably involves casting into some mold that is cooled via convection with fast-flowing liquid nitrogen (or similar).

The crystals in crystalline metals represent one solid phase, while the rest would be considered 'solvent' atoms - the bulk phase - that surround these crystals. In these crystalline metals, failure generally occurs at the phase transition between crystals and the bulk phase. Thus, the phase transitions really control the mechanical properties of the solid, since these properties are flaw-driven. Thus, by removing such 'flaws' altogether, the material would become very strong.

Looking at the link you provided, it says that the metallic glasses must be cooled at 1000°C/second, which tells me that they can only produce thin plates at this time because of heat transfer limitations. A thin slab has very good heat transfer characteristics, since it has a very large surface area per volume. When you make the slab thicker, conduction within the slab becomes the limiting step in heat transfer.

I'm not sure what effect the crystalline structure has on the thermal conductivity of metals, but perhaps removing it decreases this property. I would actually anticipate the opposite, because heat is transferred in metals by the easy passing of electrons from one atom to the next, taking its kinetic energy (which is a result of the atom's internal energy, proportional to temperature) along to the next atom. Thus, the more ordered the structure and tighter the packing, the higher the thermal conductivity should be. Thus, perhaps even a very high thermal conductivity does not allow these rapid cooling rates when the thickness of the sample exceeds a certain amount. If I'm right and amorphous metals have a higher thermal conductivity, then there's not much that can be done about having only thin samples (except if very complex processes were developed). If I'm wrong and amorphous metals have lower thermal conductivity, it may be that doping with some other material may increase the thermal conductivity and allow thicker plates to be cast, though there would necessarily be some decrease in the material properties as a result.

Here's some of the hype
Text

What I'm wondering is, if we compare a non-crystalline and somewhat equivalent crystalline alloy side by side, where might the non-crystalline be outperformed? hardness, stiffness, wear, flexibility, fatiguing, brittleness, melting temperature etc etc

 

[CycloWizard]

Originally posted by: Gibsons
Here's some of the hype
Text

What I'm wondering is, if we compare a non-crystalline and somewhat equivalent crystalline alloy side by side, where might the non-crystalline be outperformed? hardness, stiffness, wear, flexibility, fatiguing, brittleness, melting temperature etc etc

Ah, I gotcha. Well, I'll speculate on my own then send my friend an e-mail and see what he has to say.

The Liquidmetal® stuff looks like it's a very hard viscoelastic material. While all materials exhibit some degree of viscoelasticity, it is possible that the amorphous structure allows this material to exhibit greater damping capabilities. This means it would behave in a very superior manner in situations like earthquakes, where it is desirable to have the building 'flow' a little bit rather than act in a brittle fashion and fracture. It also means that the material should stand up to cyclic loading (fatigue) better.

From their site:

This amorphous atomic structure leads to a unique set of characteristic properties for the family of Liquidmetal alloys.
These characteristic properties are:
High Yield Strength
High Hardness
Superior Strength/Weight Ratio
Superior Elastic Limit
High Corrosion Resistance
High Wear-Resistance
Unique Acoustical Properties

So, specifically:
hardness - higher than traditional metals
stiffness - not addressed on their site, but I would guess it's probably actually slightly lower
wear/fatigue - better than traditional metals
flexibility - it has a higher elastic limit, which means it can be strained more and still return to its original shape, though it may depend on the loading rate (shear rate) due to its viscoelasticity
brittleness - brittleness is usually indicated by a combination of stiffness and yield strength... Since I'm guessing this has a lower stiffness and it has a higher yield strength, it shouldn't be very brittle
melting temperature - should be lower than traiditional metals, since no energy input will be needed to break the crystalline organization. Probably won't exhibit a dramatic melting temperature, but might have more of a glass transition like a thermoplastic polymer, then go into a melting transition.

 

[Darvil]

Originally posted by: CycloWizard

Originally posted by: Bladen
Wasn't it some kind of metallic alloy that was super cooled to form the crystal structure some fancy way.

They said they have to find suitable alloy mixes that allow for this to happen, the only one thus fr was like >50% platinum IIRC.

There are literally infinite crystalline structures that you can form by cooling metals in different ways. The most cutting-edge thing that I know of are superalloys being developed for light-weight, super-hard properties. They typically involve some alloy of aluminum, titanium, nickel, and possibly some other materials. The process by which these metals are made/cast largely determines the properties of the resulting material. I could mix a 5% nickel/95% titanium alloy and cool it two different ways and have completely different properties because the crystalline structures would be completely different. One of my old roommates still works for the AFRL and he tells me that they typically try to correlate grain size (some characteristic length of one phase of the metal) with the mechanical properties.

Here is a link that I found with a quick search discussing metal phases and how you might form one over the other.

Hey CycloWizard.

Thanks for your great posts. As you might suspect, I'm actually asking this question because I have to give a small presentation for my materials class.

Since alot of people are going to do the new materials (kinda hot topic I guess), I thought I would stick with the processes.

I'm really curious in the process that you've just mentioned above. Basically the part where you say that cooling it different ways can make materials have completely different properties.

Can you eleborate a bit more on this? Also could you give me some nice search terms I could use on google. I will need some solid info to do this so it would be great if I can find some sites that are solid. Would be nice to have some example materials and also pictures!

Great thanks to you.

 

[CycloWizard]

Originally posted by: Darvil
Hey CycloWizard.

Thanks for your great posts. As you might suspect, I'm actually asking this question because I have to give a small presentation for my materials class.

Since alot of people are going to do the new materials (kinda hot topic I guess), I thought I would stick with the processes.

I'm really curious in the process that you've just mentioned above. Basically the part where you say that cooling it different ways can make materials have completely different properties.

Can you eleborate a bit more on this? Also could you give me some nice search terms I could use on google. I will need some solid info to do this so it would be great if I can find some sites that are solid. Would be nice to have some example materials and also pictures!

Great thanks to you.

The processes are generally proprietary. However, you can talk about them generally by showing a phase diagram (such as those found in the link I provided above). Basically, the way it works is that if you suddenly cool the metal very rapidly from some temperature, it will maintain the structure of the metal shown on the phase diagram. I'll do an example based on the first figure in the link just to demonstrate how you could explain this.

Say you start with 80% Cadmium, 20% Bismuth. You melt the hole mess at 500°. As you cool it, it stays a liquid until it gets to about 250°, at which point it becomes biphasic (exhibiting two phases - a liquid mixture of the two and a solid composed of nearly pure Cadmium). The relative amounts and compositions of the two phases can be determined from the diagram using the Lever Rule (I can tell you about this if you haven't used it before). If you suddenly cool the lot from 200° down to very cold, you will have a solid phase that is a mixture of cadmium and bismuth. You will have a solid phase that is nearly pure Cadmium. However, if you instead continue to cool it very slowly down to 100°, you will have two solid phases: solid cadmium and a eutectic mixture of cadmium and bismuth.

I have to admit I'm a little hazy on the details of these phase diagrams, so if you want a more thorough explanation I'll have to dig out some old class notes. If you want to look for more info, I would try Googling metal phase diagram (also called a T(x,y) diagram), eutectic, or metal processing.

 

[patentman]

Might want to try these sites as well for background info/sources:

http://en.wikipedia.org/wiki/Amorphous_metal

http://www.reference.com/browse/wiki/Amorphous_solid

http://www.metglas.com/ (this is a great site for actual produicts made out of metallized glass)

http://www.metglas.com/downloads/lit/amor_elec_pow_dist_appl.pdf

www.darpa.mil/DARPATech2000/Presentations/ dso_pdf/5ChristodoulouSAMB&W.pdf (locked my pdf viewer up, so good luck)

http://mrsec.wisc.edu/Edetc/amorphous/

http://mrsec.wisc.edu/Edetc/cineplex/amorphous/ (COOL DEMOS)

http://www.wiley.com/WileyCDA/WileyTitle/productCd-3527403159.html (could try to see if you can borrow this book)

cyclowizard, I'm not sure what you said above about metallic glass formation (that they are formed by infinitely slow cooling) is correct. My understanding is that the opposite is true. As shown in the article in this link "Unlike conventional metals, which are usually cooled slowly until they fully solidify, metallic glasses must be cooled very rapidly and very uniformly to freeze their random atomic pattern in place before crystallization occurs due to the nucleation and growth of crystal grains. Four decades ago, when applications of this phenomenon were first being explored, the only way to extract heat fast enough to maintain the metal's random state was to keep the metastable material very thin through special techniques such as splat cooling, in which droplets of molten metal of quick-frozen on a cold surface. Continuous amorphous metal ribbons less than 0.1 millimeter thick could also be formed, at a cooling rate of 1 million°C per second, by pouring molten metal onto a cold, spinning wheel."

As for search terms, try these:

amorphous metal
metallic glass
metallized glass
amorphous alloy

 

[patentman]

Originally posted by: Gibsons

What I'm wondering is, if we compare a non-crystalline and somewhat equivalent crystalline alloy side by side, where might the non-crystalline be outperformed? hardness, stiffness, wear, flexibility, fatiguing, brittleness, melting temperature etc etc

See my post above where I list a link with the label "COOL DEMOS" If you have an internet connection in your class you could show the video as a demo.

 

[CycloWizard]

Originally posted by: patentman
cyclowizard, I'm not sure what you said above about metallic glass formation (that they are formed by infinitely slow cooling) is correct. My understanding is that the opposite is true. As shown in the article in this link "Unlike conventional metals, which are usually cooled slowly until they fully solidify, metallic glasses must be cooled very rapidly and very uniformly to freeze their random atomic pattern in place before crystallization occurs due to the nucleation and growth of crystal grains. Four decades ago, when applications of this phenomenon were first being explored, the only way to extract heat fast enough to maintain the metal's random state was to keep the metastable material very thin through special techniques such as splat cooling, in which droplets of molten metal of quick-frozen on a cold surface. Continuous amorphous metal ribbons less than 0.1 millimeter thick could also be formed, at a cooling rate of 1 million°C per second, by pouring molten metal onto a cold, spinning wheel."

I'm not sure about that, either, because that's not what I said at all. If you read my posts, I even cited the cooling rate (1000°C/second).

 

[Darvil]

Originally posted by: CycloWizard

Originally posted by: Darvil
Hey CycloWizard.

Thanks for your great posts. As you might suspect, I'm actually asking this question because I have to give a small presentation for my materials class.

Since alot of people are going to do the new materials (kinda hot topic I guess), I thought I would stick with the processes.

I'm really curious in the process that you've just mentioned above. Basically the part where you say that cooling it different ways can make materials have completely different properties.

Can you eleborate a bit more on this? Also could you give me some nice search terms I could use on google. I will need some solid info to do this so it would be great if I can find some sites that are solid. Would be nice to have some example materials and also pictures!

Great thanks to you.

The processes are generally proprietary. However, you can talk about them generally by showing a phase diagram (such as those found in the link I provided above). Basically, the way it works is that if you suddenly cool the metal very rapidly from some temperature, it will maintain the structure of the metal shown on the phase diagram. I'll do an example based on the first figure in the link just to demonstrate how you could explain this.

Say you start with 80% Cadmium, 20% Bismuth. You melt the hole mess at 500°. As you cool it, it stays a liquid until it gets to about 250°, at which point it becomes biphasic (exhibiting two phases - a liquid mixture of the two and a solid composed of nearly pure Cadmium). The relative amounts and compositions of the two phases can be determined from the diagram using the Lever Rule (I can tell you about this if you haven't used it before). If you suddenly cool the lot from 200° down to very cold, you will have a solid phase that is a mixture of cadmium and bismuth. You will have a solid phase that is nearly pure Cadmium. However, if you instead continue to cool it very slowly down to 100°, you will have two solid phases: solid cadmium and a eutectic mixture of cadmium and bismuth.

I have to admit I'm a little hazy on the details of these phase diagrams, so if you want a more thorough explanation I'll have to dig out some old class notes. If you want to look for more info, I would try Googling metal phase diagram (also called a T(x,y) diagram), eutectic, or metal processing.

Hey thanks. It all sounds a bit too complicated for this but I'll make it easy I guess. Do you know any real world items or things we use that goes thru this process? What I mean is 2 different type of items that have the same exact materials in them but yet because of the different properties (due to this process) they are used for different applications in the real world.

 

[CycloWizard]

Originally posted by: Darvil
Hey thanks. It all sounds a bit too complicated for this but I'll make it easy I guess. Do you know any real world items or things we use that goes thru this process? What I mean is 2 different type of items that have the same exact materials in them but yet because of the different properties (due to this process) they are used for different applications in the real world.

Sure. Carbon steel is made using this type of process. You should easily be able to find a carbon steel process diagram/phase diagram online. If not, I know I have one around here somewhere and can scan it in for you.

 

[patentman]

Cyclo, ok, you cite a cooling rate, but you also state

"Basically, traditional minimally-crystalline metals are formed by equilibrium (or 'infinitely slow') cooling. This is because crystal formation in metals is the result of more rapid cooling that freezes microstructures in place. This means that, to form a truly amorphous metal, you would have to heat the metal up VERY hot to where only one homogeneous liquid phase exists, then freeze it in the same form it has as a molten liquid. This probably involves casting into some mold that is cooled via convection with fast-flowing liquid nitrogen (or similar)."

 

[CycloWizard]

Originally posted by: patentman
Cyclo, ok, you cite a cooling rate, but you also state

"Basically, traditional minimally-crystalline metals are formed by equilibrium (or 'infinitely slow') cooling. This is because crystal formation in metals is the result of more rapid cooling that freezes microstructures in place. This means that, to form a truly amorphous metal, you would have to heat the metal up VERY hot to where only one homogeneous liquid phase exists, then freeze it in the same form it has as a molten liquid. This probably involves casting into some mold that is cooled via convection with fast-flowing liquid nitrogen (or similar)."

Ah, you're right. That was my mistake. I should have said maximally-crystalline, not minimally. Not sure where that second sentence came from, as it doesn't make sense... Too much computer time for me.

 

[Darvil]

Hey guys thanks alot for all the info.

Pantentman thanks alot.

I think I will do something on amorphous metal. Probably the process and then some highlights like the video you linked. Any other video like that? lol. I guess I could do something on the pitch too.

Thanks!

 

[martensite]

Sorry about digging up an old thread, but just to reiterate:

Amorphous (non-crystalline) metallic alloys (AA) and Bulk Metallic Glasses (BMG) are produced by non-equilibrium cooling from a single phase (typically melt state) region. The amorphous alloy thus produced is metastable and with further heat treatment, usually heating and slow cooling, can also be made crystalline if needed. Cooling rates required for creating AA/BMG are usually around 10^6 Kelvin/second, though these days, with better control of material chemistry, required colling rates have been brought down some.

The problem arises in casting thicker sections, since your cooling rate will begin to suck if you exceed anything more than a thin sheet. Often you end up getting the surface layers amorphous and the interior crytalline. This is not good.

Also, thermomechanical processing of AA/BMGs can be a bit tricky because (1) you have to stay below their glass transition temperature (Tg), otherwise you will lose the amorphous properties. So you need very high pressure to form shapes (2)AA/BMG can be very strong and hard, but also very brittle, so they will crack easily and fail without undergoing plastic deformation, when attempts are made to form these materials into useful shapes. [Catastrophic failure in structural alloys is never a good thing.]

So casting into final shapes directly is preferred. But we come across the same old problem of cooling rates for complex shapes now.

There are also alternative methods to produce AA/BMG without resorting to melting, and the most common one is high energy ball milling of elemental powders in a particular composition which produces a powder which is metastable. This has to be further compacted under very high pressure and (preferably) moderate temperature to give a bulk metallic glass/AA. But now arise problems of porosity, incomplete density etc..

IMHO, while fine for small parts, magnetic materials etc amorphous metallic alloys for structural applications are a bit overhyped class of materials which have not really delivered as promised.