Lab discovers titanium-gold alloy that is four times harder than most steels
 

Super-narrow tubes coming when??

Lab discovers titanium-gold alloy that is four times harder than most steels

It's an interesting find, but don't expect it to make any difference in our world.

It's easy to confuse hardness with strength, but they're very different things. Besides good strength, bicycle steels need good elastic properties (stiffness/flex) and toughness. Toughness is hard to define, but separates high strength structural grades from high hardness grades that might be used on cutting tools.

In fact it's steel's toughness, more than anything that is at the core of the never ending steel vs. carbon fiber debates we see here on BF. CF may be stronger, but steel is far tougher and that has a real value.

Toughness is the ability of a metal to absorb energy without cracking. Tests to determine a materials toughness typically involve putting a small notch in the test piece and hitting it with a hammer (all carefully defined and controlled, of course). Alloy steel, stainless steel, and titanium are all very high toughness materials (generally speaking). Aluminum is maybe medium toughness. Carbon fiber is very low toughness. Hardness is frequently inversely proportional with toughness (obviously not always, but that's the trend).

Sorry to nerd out on you. I'm a welding engineer, 'nuff said.

It all depends on the application. There are places where hardness is important. For example cones and races. But, one doesn't necessarily need super light cones either.

Titanium pedal spindles have had a problem with loose bearings, but are effectively being used with sealed bearings.

Maybe titanium cassettes and chainrings? No doubt if it has a gold/titanium lattice like pictured, it will be about 50/50 gold/titanium, and will be extremely expensive. Unlike some alloys that only have a small percent of the alloy agent.

that was an interesting article, because the inventors are not material scientists. So a lot of the discussion about material properties are from a relatively naive viewpoint. I'm pretty sure this is a material that is going to be used in really expensive items, not bicycles. Not sure I'm, convinced there is even a bicycle application.

The key properties for bikes is Ultimate Tensile Strength per kg (UTS/kg). Steel has a higher UTS than either CF or Aluminum, but the others are lighter, so you can use larger tubes which have higher strength.

I do not believe it. Gold is known for being soft, maybe not as soft as lead, but soft. So I do not believe you add soft to titanium and get super duper hard. Maybe they meant add diamonds to titanium.

Much of what happens when you alloy metals is counter-intuitive. Most, if not all alloys of gold are harder than pure gold. This is a common effect, and most alloys are harder than any of the pure metals mixed to form them.

So, I can't speak to the published news item, but there's nothing there to cause skepticism beyond the normal degree one should maintain with any press release.

Add carbon to iron, and one gets an alloy that is tough and malleable.
Aluminum is often alloyed with Titanium to make it tougher.

One's alloy doesn't have to truly match either base material.

Most alloys only use a small amount of the alloying agent. This may be unique with a very high concentration of both Titanium and Gold.

Just a small quibble. Large percentage mixes of two metals aren't rare. Brass (runs from 1:1 to 2:1 or so) is one notable example.

That is exactly WHY it will be used for bicycles. If it provides a 0.0000001% performance advantage, so much the better. If not - BLING - will be enough to market it.

Maybe.
The best place for such a product might be in sprockets. But, it may be heavier than using pure Titanium or Aluminum. And, say it increases the cost over an aluminum cassette by 10x. The top racers might be happy to ride with single-use aluminum parts.

Perhaps one will see it in spindles and bushings. But that would be competing with advanced ceramics.

I think most really expensive bike parts are made from relatively inexpensive materials, and any cost differential is made up with bull****.

It will be weaponized first, that was where the Wright Brothers first shopped their Airplane,. the Army.

Fortunately cycling derives quite a bit from the aircraft industry.

Chromoly 4130 was probably developed for aircraft, as was Titanium 6Al4V. Or in some cases, aircraft tubing is used to build the bikes.