MitchellH

New Titanium-glass Alloys Are Tough, Cheap And Light-weight

JBD

Yeah, but they're more dense, IE heavier.

This will never fly.

ElJamoquio

Some toughness/ductility seems to be a pre-condition of materials with high fatigue strength. That said, toughness/ductility by itself isn't of much use in a bike until you crash/crack the frame; yield strength and fatigue strength are paramount. You'd probably be better served by throwing some Kevlar in your Carbon weave.

veggiemafia

This is one of those many times since I've gotten into cycling that I regret getting my Bachelor's in English and music and not materials engineering.

Other times that happen are: every time I look at a paystub of mine; every time I think of what a nice bike I could have with my salary as a materials engineer.

ElJamoquio

PSA: toughness, in materials-terms, refers to the amount of 'energy' a material can absorb while it is breaking (permanently deforming). Brittle materials have low toughness even if they sustain high loads.


Of course, for bike frames, we want our frames to not fail at all.

MitchellH

from the article: Scientists from the California Institute of Technology (Caltech) have created a range of structural metallic-glass composites, based in titanium, that are lighter and less expensive than any the group had previously created, while still maintaining their toughness and ductility--the ability to be deformed without breaking.

I don't know, seems to me they are implying that it is lighter than titanium, though it's not completely clear.

Shimagnolo

Take it from an engineer; Proficiency in language and music attract a lot more chicks than being an engineer.

Shimagnolo

When I was in college, I remember a chemistry prof extolling the virtues of metallic glass (aka amorphous metal) with great enthusiasm. That was the late '80's. I'm surprised I've heard so little of it since.

PlatyPius

Soon I'll be able to watch the lemmings flock to the next "New! Better! Lighter! Stronger!" thing. I've already watched the change from steel to aluminum, aluminum to titanium, and titanium to carbon. People amuse me.

DannoXYZ 

Anyone remember the Specialized M2 ???

MitchellH

Aint progress a beatch? I bet you are still using down tube shifters, right?

Terex

But it had great success as a plot element in Star Trek IV: The Voyage Home, 1986.

gr@sshopper

Dangit, I was going to go for the transparent aluminium joke, but my mouse wasn't typing fast enough.

mrbubbles

Explain, I am curious.

Mr. Fly

My reading indicates that the new material is lighter than the original amorphous material and about on-par with the current aerospace alloys.


I think it's confusion between metal matrix and amorphous metal.

DannoXYZ 

The Specialized M2 was made using an aluminium metal-matrix composite with silicon-carbide crystals embedded back in the '80s. Really strengthened the aluminium and reduced a frame by about 1-2 lbs for the same strength. Around then, Teledyne made an aluminium/carbon-fibre MMC. Imagine carbon-fibre, but without the weak resin binder, instead use aluminium which provide much more structural strength. Frame was about 1/3rd the weight for the same strength of other frames at the time.

All these technological advances are great from a purely metallurgical point of view. However, there tends to be big stumbling blocks in adapting existing plants to build with the new materials. Or in many cases, all-new factories and assembly techniques have to be developed.

Usually it comes down to bang-for-the-buck value and typically you need a material with at least 3-5x the current strength-to-weight ratio at the same cost in order to make it marketable. The very first titanium frame made by Teledyne in the late '70s cost over $10k at that time. The '90s beryllium frame cost over $50k to make. Technical design exercises are fun, but it needs to have a large and clear performance benefit and you have to be able to offer it at attractive price-points in order for the material to be widely adopted.

Brian_1

Rode one all over LA (from Pasadena to Venice) back in the day. Very strong frame, but not as comfy as my Merlin Extralight. Heavens I miss riding along Pacific Coast Hwy and through Griffith Park. California rules, Arizona blows. Ask me how I know.

DannoXYZ 

Yeah, JBD mis-read the article. It basically states:The article does state that the titanium-based material is less dense than the previous zirconium ones, but did not give the actual density figures. What is implicit in the article is strength-to-weight ratios. They're trying to build materials with lower-densities to reduce total-weight, while at the same time, maintaining ALL of the original strength.

It's a wash if you reduce density while reducing strength at the same time. Such as going from steel to aluminium. While aluminium has 1/3rd the density of steel, it also has 1/3rd the strength. So you end up having to use 3x as much aluminium for the same strength as a steel part. So both parts ends up being about the same strength for the same weight, there's no savings. This wash is similar with strength-to-stiffness ratios as well. And the comparison is similar when comparing steel to aluminium to titanium. Of course it depends upon the exact alloys of each materials used, but in general that's the trend with strength-to-weight or strength-to-stiffness. However, there's other measurement metrics that may determine which to use, such as strength/stiffness-to-cost ratios.

The trick then is to come up with new alloys or composites of these materials with new properties. One material that blows them all out of the water is beryllium. It's not only lower in density than steel/alloy/titanium, but it's also stiffer and stronger as well. However, it has a very high cost and requires extremely expensive fabrication techniques.

Terex

And is a Category 1 carcinogen, along with other toxic properties.

jonestr

I remember reading a SciAm article a few years back about amorphous metals, which are metals that have been heated and then rapidly cooled so the material cannot configure itself into a crystal form, and one of the main problems was that cracks could propagate very easily due to the lack of structure in the material. At one point golf clubs had been manufactured from this stuff and the first hit would be amazing and on the second hit the club head would shatter. The solution was to wrap the amorphous metal with a crystalline metal so as to keep small cracks from propagating. This is what would have to be done to make frames, and might limit how light you could make frames from this material.

JBD

Yeah, I was kinda reading in between the lines there, since Ti, as they said, has a density of 4.5-5*, and cubic zirconia** has a density of 5.6-6*, naturally (I would presume) alloying the denser into the 'lighter' would make the latter denser. Whether the increased density is an issue or sufficiently offset by the other advantages is another matter.


I was about to use the article as a jump pad for steel, but had instead decided to make a lame weight weenie joke instead.

To be honest, if the implications of the article are to be believed, great things could come from this new material for many industries beyond the two mentioned.



*densities given in terms of SG
**I picked cubic zirconia because it was most likely to have a readily available SG which in all honesty fcc, bcc, etc. are a little beyond the realm of this conversation aren't they?

ElJamoquio

I think they've managed to make it without the fcc/bcc structure, correct? The basic definition of a glass as I recall it, is that it has no structure.

jccaclimber

Unless the chick is an engineer as well (as mine is).
PSA part 2: NONE of the following words mean the same thing
Toughness
Strength
Stiffness
Hardness
Ductile
General trends may arise, but they are not the same.

JBD

I picked cubic zirconia because it was easy...

the aside was so that I wouldn't have to backpedal any more than I have...

monporn

Steel. Steel and more Steel.
*wakes up*
maybe, maybe not...and if so will be stupidly pricy.