Titanium
Titanium fasteners offer strength, low weight, and excellent corrosion resistance.
Titanium fasteners are ideal for marine applications due to their excellent corrosion resistance. Grade 5 titanium (due to its high aluminum and vanadium material content) is the strongest of all the titanium alloys. Grade 5 titanium is 60% the weight of 316 stainless steel but is harder and stronger.
Titanium fasteners are popular in aerospace applications due to their strength : weight ratio.