Gum metal
Gum metal, also called TNTZ, is a unique titanium alloy with high elasticity, ductility, and yield strength. While originally developed with a composition of 23% niobium, 0.7% tantalum, 2% zirconium, and 1% oxygen, it can exist over a range of compositions and also include vanadium and hafnium. Applying cold work to gum metal actually decreases its elastic modulus, with reported shear moduli as low as . At the same time, cold work increases gum metal's yield strength. By using a heat treatment after this cold work, some elasticity can be sacrificed for even greater strength, with yield strengths ranging as high as , on par with some of the strongest steels. "Gum metal" is a registered trademark of Toyota Central R&D Labs and was initially developed there. The results of that research were first published in April 2003. References 

Titanium alloys