http://www.roymech.co.uk/Useful_Tables/Matter/Titanium.htmlhttp://www.roymech.co.uk/Useful_Tabl.../Titanium.html

You can see here there are many grades of titanium. Their properties and uses are down to the other materials alloyed (mixed in with) the titanium.

As far as we are concerned with robots,

grade 2 - flexible and will bend on impact
grade 5 - Stronger but will tend to tear instead of bend