[Leica] Re: LUG metallurgist

[Frank Dernie <Frank.Dernie@btinternet.com>]

Hi Dennis - this is getting really OT - but Titanium is actually not an 
ideal choice of material in most parts of a racing car. It is suitable 
for bolts and studs in some places, and join inserts. High alloy 
aluminium is a better choice in most places because the specific 
strength is very close and it is MUCH easier to machine, and cheaper. 
Titanium shares the same specific stiffness (stiffness per weight 
simply) with most metals (berillium is a notable exception) so anywhere 
where stiffness is the limiting factor all metal parts will be the same 
weight at the same stiffness unless the geometry is changed. Carbon 
composites are better than all the metals for everywhere the 
temperature is appropriate - cost is an issue(!) to the extent that an 
agreement has been reached to limit its use in some engine parts, 
engine speeds will be up to 20,000 RPM by the end of this season anyway.
IMO Magnesium is a horrible material. It is weak, brittle but soft, has 
high thermal expansion and corrodes badly. When I changed my EOS D30 
for a D10 it was the one thing which made me hesitate. An aluminium 
internal skeleton with a polycarbonate external shell is a MUCH better 
choice IMO, but MUCH more expensive to manufacture and has an inferior 
marketing image.
I am the FIA technical delegate for Thoroughbred Grand Prix cars and 
the biggest problem in these cars is the deterioration of magnesium 
parts.
I believe you are right wrt Ag and Cu. My knowledge is very skewed now 
- - it is a long time since I had a general education - and whilst I have 
a reasonable knowledge of the materials used in racing cars I don't 
know much about others! I am still disgusted by the marketing page of 
the people selling Ti cookware though.
cheers
Frank

> Dennis Painter  asked
>
> Frank Dernie wrote:
>
>> Quite correct Jerry, also the F3 titanium has a titanium top, prism
>> cover and baseplate - some were painted a "titanium" colour - it does
>> seem that titanium is frequently used to describe a colour rather than
>> a metal these days. Subsequent F3 titaniums were painted black I
>> believe. The Olympus OM4Ti has titanium top and bottom plates also,
>> most are painted black. Titanium, as you know but it seems others
>> don't, is much lighter and harder than brass and is much more 
>> difficult
>> to press or machine.
>> I suppose titanium is a bit of a buzz word at the moment, like turbo a
>> few years ago. Plenty of items are sold in a titanium colour just now.
>> I was mystified by the titanium coated Leica. It does look nice but
>> both the black and natural chrome plates which have been offered since
>> the M5 are very robust so it really has only styling as a 
>> justification
>> IMO.
>> Frank
>
> Hi Frank,
>
> How do the superplastic Ti alloys figure into forming? Any 
> applications in
> F1? Could this technology carry over into the camera field? I do 
> notice use
> of magnesium castings now on some digital cameras. Looks like a good
> materials application as that stuff is light and much easier to cast 
> than
> Ti.
>
> Regards,
> Dennis
>
> PS: right about the thermal coefficient for Ti in cookware. I think Ag 
> has
> the best coefficient but a bit expensive compared to Cu.

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