riff_raff wrote:n smikle,
Lots of titanium fasteners are used because they are lightweight and have good compatibility with carbon composites. Care must be taken with titanium fasteners though, since their threads readily tend to gall/seize. Titanium is also very notch sensitive, so any fastener that is nicked or gouged must be replaced.
Multiphase steel alloys (like MP35N) are used where very high strength is needed, but not corrosion resistance.
718 Inconel has a good combination of strength, corrosion resistance and high temperature capability.
13-8PH stainless has good strength and corrosion resistance.
Hope that helps.
The cobalt nickel alloys MP35N and MP159 actually have a better corrosion resistance than nickel based superalloys such as Inconel 718. They offer a higher strength too, but cobalt alloys are expensive. They are usually the choice for high temperature corrosive environments where alloys such as Inconel isn't up to the task.
http://www.spstech.com/aero/prod_lit/su ... ochure.pdf
For fasteners attached to carbon fibre bits titanium is a good choice since it's a very noble metal, close to graphite in the galvanic series.
Of course, a high quality screw is forged and has rolled threads.