Is titanium only a matel used for aerospace applications? why not in common vehicles?

Titanium metal is associated with aerospace applications, in addition to some marine applications and few other uses. The demand for that depends on aviation industry developments.. Whereas it is a light weight, strong and non-corrosive "smart" metal which can be used in car making to decrease weight and therefore needed engine power that would in the end save massive fossil fuel. Does anyone involved in global warming know anything about this controversial situation?

Check out:
-The cost of titanium
-The energy needed to extract it from ore
-It's scarcity compared to steel

and you might work out why we only use it where we really need it!

Russian submarines use it also my friend has a mountain bike there are watches and loadsa things.......

some cars are built from aluminium i suggest this to help lower emitions

"Because the metal reacts with oxygen at high temperatures it cannot be produced by reduction of its dioxide. Titanium metal is therefore produced commercially by the Kroll process, a complex and expensive batch process. (The relatively high market value of titanium is mainly due to its processing, which sacrifices another expensive metal, magnesium.[5])"

Translated: its too expensive to produce.

Because common vehicles don't go to space.

No controversy here, it is economics. On the up side, more automotive parts are being made of plastic and Al alloys. Al is even less dense than Ti although Al alloys that are as strong as Ti are much more expensive (Al aerospace alloys). The biggest thing about the efficiency of autos is what the customers demand. The demand for hybrids, high mileage diesel and gas autos has been growing but people are also still buying Hummers and SUVs.

In addition to all of the other answers; even without the cost disadvantages, in most situation where high temperature is not involved, aluminum makes more sense from a strength/stiffness/weight standpoint.

If you want to look at really interesting material, check out Silicon Carbide.

I am a Mechanical Design Engineer.

Titanium is also used for medical purposes. In spinal surgeries titanium is used for plates, spacers, screws, in general anything that is meant to be implanted in the human body and stay there.

The cost and scarcity of titanium would prohibit it being used in something like cars that are mass-produced in such quantity.

As well as the difficulty, hence cost, of making the material, it is also difficult to machine, so more time means more cost. Also it causes high wear on cutting tools, again increasing cost.

It also has a tendency to be difficult to undo when used for bolts, etc.

Unfortunately the desire for lighter cars, which will give some (although not major) reduction in fuel usage is at odds with the desire (and laws) for improving crash safety, and the desire for features such as electric windows and air-conditioning. A medium size car from the 1970s might have been 750kg, now it's more likely to be 1300kg - an unfortunate side-effect of "progress".

Edit: It's also difficult to weld, so again increasing cost.

The enegy cost of titanium is too high to justify
it's use for energy conservation. It would be a
losing proposition for that reason.

There are several reasons, most have already been covered, but I thought I would renumerate them:
1. Titanium is much more expensive than steel or aluminum
2. Titanium alloys are difficult to form (i.e. that don't roll well)
3. Titanium alloys wear out machine tools faster than steel or aluminum.
4. Titanium doesn't have good wear properties.

Titanium is very abundant but difficult to extract and so has a high cost in metallic form.

The use of titanium for automotive parts has been debated for many years with attempts to make exhaust pipes, suspension springs, valve springs and connecting rods all proving too expensive (or using cheap alloys which were too brittle) - even the newer "low cost Beta alloys".

In the end it comes down to very simple economics - the cost of reducing vehicle mass must be attractive to the manufacturer.

For further information check out:
National Metals Technology Centre strategic review of the titanium industry (www.namtec.co.uk)
Foresight Vehicle report on development of cars (can't remember the URL)
Titanium Information Group handbook on titanium in vehicles (www.titaniuminfogroup.co.uk)