Titanium-Niobium Elastic Modulus Reduction

Niobium lowers stiffness in titanium, that's the trick with implant alloys. Material that's too stiff doesn't transfer enough load to the bone, that's called stress shielding. When welding, you have to be careful not to alter the structure again and make the part stiffer. Keep heat input low and let it cool slowly, then the desired softness in the material is preserved.