New strongest material

A press release from UCLA says they’ve found a material (a mixture of magnesium-zinc alloy and silicon carbide nanoparticles) that has the highest specific strength and specific modulus (stiffness to weight ratio) of any metal.

The press release was lacking numbers, but is based on a paper in Nature which, of course, is behind a paywall. Anyone have a subscription to that magazine who could look the paper up and see if they give numbers?

Also, any idea of how long it will be before we see this material in production? It seems the only advance is a technique to disperse the nanoparticles in the metal so they don’t clump, so perhaps there won’t be a long wait.

First of all thanking you for this brilliant commentary and I like this. I expect this will be very helpful to the students to complete their educational works related with the topics.

Ok, so “in stock” check list…

  • magnesium … in stock
  • zinc … in stock
  • a furnace for keeping a mix of magnesium and zinc molten… in stock
  • silicon carbide nanoparticles … um do we measure the cost of these in Dollars per nanoparticle ? Not in stock
  • a machine for handling nanoparticles and ensuring they go into the Mg Zn alloy … ? Nope
  • A Treatment for SiC nanoparticle polution of the lungs… it can’t be good to breath that stuff. Not in stock.
  • Does it blend test ? not in stock. but don’t breath it, until proven safe.

My main point is that its one thing to measure the strength of a grain of Mg Zn - Si C crystal in the lab, its another to be able to successfully and safely handle Si C nanoparticles.
I guess you want to make them right there above the Mg Zn … But still, does SiC really want to dissolve into the metal ?

UCLA says they have solved THAT. That they can get the SiC nanoparticles to avoid each other (no scale of SiC or cloud of dust, no SiC microparticles) and hence produce nanoparticles that go into the Mg Zn.

In the past, the SiC remained interstitial to the metal crystals, and they say they can get the SiC inside each grain … to strengthen each grain.

Well, UCLA say they have a manufacturing process developed.

Its one thing to measure the strength of a grain of Mg Zn - Si C crystal in the lab, its another to be able to successfully and safely handle Si C nanoparticles.
I guess you want to make them right there above the Mg Zn … But still, does SiC really want to dissolve into the metal ?

UCLA says they have solved THAT. That they can get the SiC nanoparticles to avoid each other (no scale of SiC or cloud of dust, no SiC microparticles), and go straight into the metal , avoiding air pollution, and they actually produce the grains of Mg Zn alloy with 10% Si C internal to each grain.
In the past, the SiC remained interstitial to the metal crystals, but UCLA says they can get the SiC inside each grain … to strengthen each grain. That is why they supplied a photo of a grain… to say “its in there, not some sort of encasement”.

They also said “scalable” which means to say that its not just a nano-scale lab test, it should be a process that can make tonnes in hours (or other industrial sized units … lots of material in short time), rather then nanograms in months.
Here’s the press release direct from UCLA, which is a bit more detailed.

I want to be the first to build an archery bow out of it, it might give me a significant lead in the arms race I have been engaged in.

Well, yes, Isilder, I can think of several issues myself that you didn’t think of. For instance, does this material shed silicon carbide particles when machined or in use (under vibration)?

But I’d really like to know how much better than carbon-fiber and titanium it is. Does it really have the potential to revolutionize spacecraft, planes, autos, etc.? We really need numbers to say for sure. The press release has no numbers; I want to know if the scientific paper has them.

I wonder what effect the zinc and nanoparticles have on the flammability of the magnesium?

I get the impression from my reading that magnesium alloys are somewhat (although not by a lot) less flamable than pure magnesium, so I would expect that to be true of this composite. Could be wrong and it’s something they’d have to test once they make it in sufficient quantities. Magnesium in bulk is actually fairly difficult to ignite. In flares, the magnesium is in forms that have high surface areas: thin wires or powders or something.

It’s not like we don’t have experience using magnesium as a structural metal. It and its alloys are used in a number of applications where low weight is important but very high strength is not. This material would let us use it in places where high strength is required as well.

Turns out I have access to Nature at work. Testing was carried out on the microscale. A few quotes with numbers:

Fig 3h is a comparison to other engineering materials:

The figure shows their material (“HPT-processed Mg2Zn (14 vol% SiC)”) with a specific modulus of about 45 MN-m/kg and specific strength of about 350 kN-m/kg. This is compared to the closest competitor (“Mg10Al (1 dimondoids)”) at about 35 MN-m/kg specific modulus and about 250 kN-m/kg specific strength.

Thanks, zut. I’m not a mechanical engineer, but AFAICT, those numbers do look good. But it looks like they haven’t made any large pieces of this material, despite them saying the process scales. I think I’ll wait before getting excited.

For reference, if you haven’t seen it, compare to the numbers on this chart. The reported combination of specific strength / specific modulus is pretty solidly in the middle of the carbon fiber reinforced polymer area, and under that of ceramics… but well above almost all metal alloys. The paper also reports a metal-like maximum strain of ~30%.

They did do tests at two different (but still micro-) sizes without much difference in properties. Also, based on previous research by other people, they imply that the measured strength should scale up to bulk sizes. I’m a bit skeptical, but not my field.