Why is titanium so brittle?

Because it's not brittle. You will not find one metallurgist, one, in the entire world that will say that titanium is brittle (and if you do you can, from that, declare his incompetence!). It simply isn't. On the contrary it is one of the toughest materials around. read more

So this impurity, which could be just a nitrogen or oxygen atom, can create a much larger obstacle by moving the slip plane to another direction. (shown in green below) The titanium atoms no longer have a straight slip surface to glide on. That is how titanium becomes brittle with just a few extra atoms of oxygen. read more

Its density is 4.6 grams per cubic centimeter. Titanium metal is brittle when cold and can break apart easily at room temperature. At higher temperatures, it becomes malleable and ductile. Malleable means capable of being hammered into thin sheets. Ductile means capable of being drawn into thin wires. Titanium has an interesting physical property. read more

While aluminum is the third most abundant element in Earth's crust, titanium ranks only ninth. Even so, it's still found in virtually all rocks, sands, soils, and clays, as well as in plants, animals, and water. Like aluminum, titanium's readiness to react with oxygen means it is never found on Earth as a pure metal. read more