The Sexiest Metal

jonerik writes "Denver's weekly Westword magazine has this article on titanium and the attempts to break it out of its traditional aerospace/defense industry niche, including its growing use in architecture, computers, jewelry, sports, knives, cars, medicine, and other areas. The upside: It's as strong as steel but weighs half as much, it doesn't rust, and it's fairly plentiful. The downside: It's expensive compared to steel and aluminum and its high melting point makes it difficult to work with under some conditions. Still, it's nice to see it being used in other applications." Heck, I know someone who used it as his wedding ring. Pretty cool, actually.

Comments

Titanium is also very flexible.

[Flarners]

Titanium may be as strong as steel, but it's far easier to bend when cut thin. Anybody who has one of the titanium PowerBooks will attest to the fact that if you try to pick them up from one end, the thing will bend disturbingly. This is why you won't see titanium in kitchen sinks, silverware or anywhere else where the metal needs to be thin, strong, and unflexible. The only thing it has going over steel in these cases is buzzword compliance and price (if it's more expensive, it must be better!)

Re:Titanium is also very flexible.

[dhovis]

Oh Boy.

Puts materials scientist hat on

The TiBook is made from commertially-pure (CP) Titanium. This is basically an unalloyed grade and is very weak relative to the better 6-4 (6%Al-4%V) "aircraft grade" Titanium alloys.

This is the thing. Apple chose Titanium more because it was sexy than anything else. You see a lot of things advertised as "Titanium", and often times the Titanium plays no important role in the product. There are some golf balls out there that has some Titanium in one of the resins close to the core, but the Ti is not in metal form, and is really only there in minute quantities.

In fact, sometimes titanium overshadows everything else there. One of the responses mentions "Titanium" glasses frames that are very flexible. Those are not pure titanium. They are a 50-50 alloy of Titanium and Nickel. It is a "shape-memory alloy" which has the ability to deform easily by realigning the crystal structure when bent! and then shifting the crystal structure back when the stress is removed. They are way cooler than just titanium. They have been precision engineered to be superelastic.

Titanium may be sexy, but it is not always the whole story. The marketing people often latch on to it, but as it becomes more common (and it will), it will start to lose it's allure. A large part of the cost of titanium is in refining it from the ore, and I've heard about a few developments that might bring it closer to the cost of aluminum in that respect.

Re:Titanium is also very flexible.

[b_pretender]

This is the thing. Apple chose Titanium more because it was sexy than anything else. You see a lot of things advertised as "Titanium", and often times the Titanium plays no important role in the product. There are some golf balls out there that has some Titanium in one of the resins close to the core, but the Ti is not in metal form, and is really only there in minute quantities.

Titanium Dioxide, commonly referred to as rutile, is a form of titanium. This is commonly found in most white pigments and dies. Chances are, the white golf ball has rutile, and thus titanium, in the dyed plastic coating. Gold balls are usually white, and I wouldn't be surprised if most of them contained rutile.

Kitchen sinks, stoves, refrigerator, bath tubs, many have a porcelain coating and rutile is the whiteness in the coating. Even your green stove has a white rutile base prior to adding green pigment.

That being said, I agree that structurally, it would have been better to use steel or alluminum for the case of the PowerBook. However I own a powerBook, and, although flexible, I prefer it's titanium, although polished aluminum would be cool too.

The coolest thing about titanium, that often get's looked over is its resiliancy. It makes it ideal for applications where steel and aluminum are useless. Look at bicycle frames, for example. Steel frames have been around for years and they have been optimized to be ultralight, strong, yet flexible enough for a comfortable ride. Aluminum came along, and although lighter than steel, it made for a rigid stiff frame and a toothshattering bike ride. The *design* of the aluminum frames could have been altered to allow for more resiliency, but the problem with aluminum is it fatigues and breaks if it flexes to much, so redesigning the frame to be more flexible was out of the question. Fortuneatly, suspension bicycles need a high stiffness in order to keep hinges/shocks/etc. lined up straight, so aluminum is ideal for this purpose.

Titanium, although not as strong as steel and not as light as aluminum, offers resilience. The first Ti mountain bike frames were awful, built similar to their steel counterparts, and compared to riding a wet-noodle rather than a bicycle. Over the years, the design of Ti bikes has caught so that the frames are resilient in all of the right places, while still remaining sturdy in the other places. Some frames have even used this resilience as the suspension and put a damper/shock into the frame to allow for suspension travel and damping in a metal frame with NO hinges.

Ti Wedding Ring?

[4of12]

If you haven't been married for long you probably don't know that sometimes, when people gain weight, the rings start to become, uh, constrictive.

With a traditional soft gold alloy you can snip the tight ring with a pair of bolt cutters or even wire cutters for thinner gauge rings.

With titanium, I don't think you'd have such an easy time removing a stuck ring. A cutting torch is not going to leave much of a finger and using a diamond saw, too, could be real tricky with in vivo parts involved.

Get ready for gangreme to set in, unless you lose a bunch of weight in a hurry or find a good lubricant.

Re:Ti Wedding Ring?

[banuaba]

When I did volunteer EMS in rural NJ, we had this thing in our rig called a 'ring remover'. It removed rings with a little saw blade, and it was nigh impossible to damage the patient's finger with the cutter. Ti was on the list of metals that it would cut. So I wouldn't be *that* worried.

Alloys

[Anonymous Coward]

For most applications it is Titanium 6-4, very hard and very tough:
- 6% aluminum
- 4% vanadium
- 90% titanium

For bicycle frames, Titanium 3-2.5 is used as it is more ductile (for forming seamless tubes) and has a better stiffness in torsion (which is needed as pushing on one peddle then the other torques the frame back and forth):
- 3% aluminum
- 2.5% vanadium
- 94.5% pure titanium

Welding?

[markmoss]

Anyone here welded titanium? I wasn't a welder in the Air Force, and it was a long, long time ago, but IIRC the metal shop had to drag out all sorts of gear if welding Ti was necessary. I think you have to flood the weld area with nitrogen because its ignition temperature in air is lower than the melting temperature. Of course, you need something much hotter than the normal welding torch. Then you get the weld done and need to grind down the excess bead -- and as hard as Ti is, that's going to take some time.

But it's mighty durable once it's together.