Gum metal

Titanium alloy with high elasticity

Not to be confused with Gunmetal.

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.[1][2]

Applying cold work to gum metal actually decreases its elastic modulus,[1] with reported shear moduli as low as 20 gigapascals (2,900,000 psi).[3] At the same time, cold work increases gum metal's yield strength.[1] 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 2 gigapascals (290,000 psi), on par with some of the strongest steels.[3]

"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.[3]

## References

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1. ^ a b c Saito, Takashi; Furuta, Tadahiko; Hwang, Jung-Hwan; Kuramoto, Shigeru; Nishino, Kazuaki; Suzuki, Nobuaki; Chen, Rong; Yamada, Akira; Ito, Kazuhiko; Seno, Yoshiki; Nonaka, Takamasa; Ikehata, Hideaki; Nagasako, Naoyuki; Iwamoto, Chihiro; Ikuhara, Yuuichi; Sakuma, Taketo (18 April 2003). "Multifunctional Alloys Obtained via a Dislocation-Free Plastic Deformation Mechanism". Science. 300 (5618): 464–7\. Bibcode:2003Sci...300..464S. CiteSeerX 10.1.1.74.9524. doi:10.1126/science.1081957. PMID 12702870.
2. ^ Talling, RJ; Dashwood, RJ; Jackson, M; Dye, D (June 2009). "Compositional variability in gum metal". Scripta Materialia. 60 (11): 1000–3\. doi:10.1016/j.scriptamat.2009.02.044.
3. ^ a b c Nishino, Kazuaki (September 2003). "Super Multifunctional Alloy "GUM METAL"" (PDF). R&D Review of Toyota CRDL. 38 (3): 50. ISSN 1347-9652. Retrieved 29 July 2011.