Q: Do titanium screws break?
A: Any material can break in the wrong conditions. Titanium offers excellent high strength: Grade 5, 148 ksi UTS and 138ksi yield and Titanium Grade 2, 70ksi UTS and 50 yield. If the conditions require a stronger bolt, the titanium will fail. Strong acids can corrode titanium which may lead to premature failure. Also, if you use a titanium screw at high temperatures (higher than about 500F), this will also weaken the titanium and cause it to fail.