Titanium
Titanium alloys are used in aerospace engineering to make very strong and light parts of aeroplanes. These alloys can replace steel because they are almost as strong as steel but much lighter. They are also much stronger than aluminium alloys, but only a little heavier, meaning that titanium parts can be thinner and lighter, while still withstanding the same forces. It does not corrode in most conditions, even when exposed to sea water or chlorine. However, it can burn at high temperatures, and like many metal powders, titanium dust is extremely flammable.