Metallic Glass - Stonger Than Steel, Just As Tough and Now Cheap!

Metallic Glass has been around since the 60's. But it has always been cost prohibitive to make. Its truly amazing stuff. As, I said in the title it is stronger than steel or titanium, its just as tough and you can mold it like plastic. Now a new process has been developed that makes it cheap to make.

Strong, Tough and Now Cheap: New Way to Process Metallic Glass Developed

Stronger than steel or titanium -- and just as tough -- metallic glass is an ideal material for everything from cell-phone cases to aircraft parts. Now, researchers at the California Institute of Technology (Caltech) have developed a new technique that allows them to make metallic-glass parts utilizing the same inexpensive processes used to produce plastic parts. With this new method, they can heat a piece of metallic glass at a rate of a million degrees per second and then mold it into any shape in just a few milliseconds.

"We've redefined how you process metals," says William Johnson, the Ruben F. and Donna Mettler Professor of Engineering and Applied Science. "This is a paradigm shift in metallurgy."

Evidently this new process allows the metallic glass to be heated and molded so quickly that the crystallization that can weaken does not have a chance to form. Supposedly, this stuff could be used for anything from a cellphone case to aircraft parts and all manner of things in between.

If it is as strong, tough and cheap as they say it could have a great impact.

reply to post by Frogs


Wow transparent too. I can't even see it.

Whoop...there it is!

Thanx.

Heh - see my edit.

First thing I did after typing the title in the OP was hit tab and then enter. I guess that was enough to make a post.

Any predictions on what this will do to the steel/coke industry?

Or will this be swept under the rug like most of the other ground breaking technological advancements?

Will be an awesome military tool then, especially if stronger than the metals you mentioned!

reply to post by NuclearMitochondria


One thing that wasn't clear to me from the article is how big a part they can do now with this technology. The parts in the article are pretty small, but could it be used to make say a rifle barrel or automobile frame? I'm sure it could it time - but its not clear (to me) if things that big can be made with it yet.

From the article doing this takes very rapid heating...

To heat the material uniformly and rapidly, they used a technique called ohmic heating. The researchers fired a short and intense pulse of electrical current to deliver an energy surpassing 1,000 joules in about 1 millisecond -- about one megawatt of power -- to heat a small rod of the metallic glass. The current pulse heats the entire rod -- which was 4 millimeters in diameter and 2 centimeters long -- at a rate of a million degrees per second. "We uniformly heat the glass at least a thousand times faster than anyone has before,"

I don't know how scalable that is to big items at this time.

reply to post by Frogs


That's a -lot- of power.

You could scale it a bit better by pre-heating stock up to a certain temperature before applying ohmic heating - much less demand on an electrical system. You may, however, run into issues with oxidation with such methods.

The main problem is how fast they want to heat that much material. Going from room-temperature up to the stated temperatures using just ohmic heating places a lot of strain on the surge-current supply and the switching devices. By pre-heating parts so that you have a much shorter 'jump' to the glass transition phase, you can substantially reduce this requirement, and strain on the systems (or, at least in theory, use those same systems to make larger parts).

Exactly how much larger would simply be a matter of infrastructure. What are their surge and switching limits? What are the physical limitations of the system? What are the dynamics of the cooling process - parts of a certain mass/area ratio may not be able to be cooled rapidly enough to prevent crystallization. Similarly - depending upon how ohmic heating is applied (is it applied through the shot into the die or is it simply a one-time deal?) it may not be possible to make parts of certain dimensions without multiple consecutive shots - doing this opens up the possibility of part defects along where these separate injections merge.

Really, diecasting has a number of "dark arts" to it - lessons only experience and toiling over drafts and process-related part failures can teach you. This is fairly similar to that field - and while it may share many similarities to plastics - it metals are considerably more finicky materials, and is closer to the field of aluminum and zinc alloy die-casting.

It should be interesting what emerges from this.

An article discussing more recent work by the same university: www.sciencedaily.com...

"Our game now is to try and extend this approach of inducing extensive plasticity prior to fracture to other metallic glasses through changes in composition," Ritchie says. "The addition of the palladium provides our amorphous material with an unusual capacity for extensive plastic shielding ahead of an opening crack. This promotes a fracture toughness comparable to those of the toughest materials known. The rare combination of toughness and strength, or damage tolerance, extends beyond the benchmark ranges established by the toughest and strongest materials known."

The initial samples of the new metallic glass were microalloys of palladium with phosphorus, silicon and germanium that yielded glass rods approximately one millimeter in diameter. Adding silver to the mix enabled the Cal Tech researchers to expand the thickness of the glass rods to six millimeters. The size of the metallic glass is limited by the need to rapidly cool or "quench" the liquid metals for the final amorphous structure.

"The rule of thumb is that to make a metallic glass we need to have at least five elements so that when we quench the material, it doesn't know what crystal structure to form and defaults to amorphous," Ritchie says.

I suppose that addresses one of the issues related to scalability.