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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.
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
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.
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The internet is the greatest source of biased information in the history of mankind.
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.