>Tungsten's only rival for this kind of application is the radioactive element uranium. Depleted uranium is (almost) as dense as tungsten and has an added advan

>Tungsten's only rival for this kind of application is the radioactive element uranium. Depleted uranium is (almost) as dense as tungsten and has an added advantage - from a military perspective - that it burns at the extreme temperatures generated as you punch your way through steel tank armour. It's also self-sharpening (ie rather than smooshing like plastic on contact, parts break off and leave a sharp edge behind like flint), and because it's effectively subsidized by power generation and the nuclear program it's extremely cheap compared to Tungsten. Tungsten alloys are tougher[1] (actually, some of the toughest materials period) but penetration depends heavily on the armor type. Hell, tungsten is toxic too and the military's biggest motivation is probably just as a really effective PR move. Uranium is definitely worse though, and I'm glad the US doesn't use it in munitions much. Uranium forms oxides that are very bioavailable (and even absorbed as gas through the lungs), and are really bad for you and even worse if you get pregnant. [1]: http://www.cam.ac.uk/sites/www.cam.ac.uk/files/news/research/news/110908-granta-design-chart.jpg http://www.cam.ac.uk/sites/www.cam.ac.uk/files/news/research...