during extreme temperature changes. temperatureextreme during stabledimensionally remain and loading under deformation resistto composite matrix metal the allows it because tant thermal stiffer and stronger,a offering composite lighter,matrix metal a form toreinforcingphase a as material nanoscale a uses method Goddard’susefulness. its limit which of stiffness—all it stability,dimensional high features 36 Invar While (CTE). expansionthermal of coefficient low very a featuring alloynickel-iron a 36, Invar® strengthening for method a developed researchershave Goddard NASA National Aeronautics andSpaceAdministration www.nasa.gov Nanophase Dispersion Strengthened Invar 36 Invar Strengthened Dispersion Nanophase Telescope. WebbSpace James the onboard instruments attach to used be to 36, Invar from fabricated fitting, metal a depicts image left top The optics suffers from low strength, high density,low high strength,and low fromsuffers various expansion characteristic of Invar 36. This is impor is This 36. Invar of characteristic expansion material while still maintaining the very lowvery the maintaining still while material Conceptual method offers a stronger, more useful Invar 36 stronger,Invar a useful offers more method Conceptual conceptual specific - • Benefits • • • resulting in lighter structures lighter in resulting resistance creep and strength Increased density Lower Stable Microstructurally CTE low Very Invar 36 Invar tion configura- loading given a for ness greater dimensional stability dimensional greater offeringtemperatures cryogenic at transformation phase undergo variation temperature despite shape and compared with conventional with compared : Reduces section thick - section Reduces : : Maintains dimensions Maintains : : Reduces mass, Reduces : : Will not Will : technology Technology Details How it works Invented in 1896 by Swiss physicist Charles in solution. In addition, the use of high-purity Applications Edouard Guillaume, Invar is an iron-nickel iron and nickel starting materials in Goddard’s Potential applications alloy with a uniquely low CTE. Guillaume process ensures optimum thermal expansion for this concept method received the Nobel Prize in physics in 1920 properties by minimizing the presence of include: for this discovery, demonstrating its impor- contamination in the alloy, which could other • Mounting and sup- tance in scientific instruments. Despite this wise degrade thermal expansion properties. port structures for importance, Invar 36 is a solid solution that Finally, unlike other strengthening attempts, satellite-based optics and cannot be strengthened through heat treat- the composition of the dispersed phase in precision sensors ment and therefore suffers from low strength. Goddard’s process is chosen to minimize ther- • High quality telescopes, In addition, its high density results in low mal expansion mismatch between the Invar 36 binoculars, cameras, specific stiffness. These characteristics make matrix and the individual particle, thus mini- lasers, and optical sights structures heavy and necessarily result in a mizing thermal stresses in the matrix over a mass penalty when incorporated in space- wide range of temperature change. • Laser rangefinders and other surveying equipment flight designs. Despite these shortcomings, it is often used in satellite structures due to its This innovative process is capable of produc- • Metrology equipment low CTE, enabling structural stability despite ing a unique, mass-saving, damage-tolerant, • Precision instruments temperature fluctuations such as those seen dimensionally stable aerospace structural such as optical benches, in space environments. Goddard’s Nanophase material. optical metering compon Dispersion Strengthened Invar 36 addresses ents, and support the shortcomings of the traditional Invar 36 Patents structures by employing a metal matrix, which is rein- NASA Goddard is seeking patent protection for • Support structures forced with an inert, nanoscale dispersant. The this technology. Invar® is a registered trade- for laser-based opto dispersant acts as a reinforcing phase through mark of Imphy Alloys. electronics used in Orowan strengthening, a phenomenon that spectrometry results in dispersion hardened metals having Licensing and Partnering Opportunities • Mandrels, molds, and a high rate of strain hardening. The dispersant This technology is part of NASA’s Innovative tooling where precision is is synthesized separately and then introduced Partnerships Program Office, which seeks to required into the iron-nickel matrix during a secondary transfer technology into and out of NASA to • Precise mechanical clocks process such as powder metallurgy. The result- benefit the space program and U.S. industry. and scientific instruments ing metal-matrix composite (MMC) retains the NASA invites companies to consider licensing unique thermal expansion and stability prop- • Resonant cavities for the Nanophase Dispersion Strengthened Invar VHF/UHF and microwave erties of Invar 36 while also achieving lower 36 method (GSC-15158-1) for commercial components density and higher specific stiffness with a applications. 50% increase in yield strength measured at • Shadow masks for photo 0.2% offset. For information and forms related to the lithography technology licensing and partnering process, Why it is better please visit the Licensing and Partnering page. Goddard’s process differs from previous attempts to strengthen Invar 36 while main- taining its low CTE in several ways. For For More Information instance, prior attempts to form an in situ If you are interested in more information or composite by introducing solutes such as Mo want to pursue transfer of this technology and C that later react and precipitate through (GSC-15158-1), please contact: heat treatment to form Mo2C, have met with limited success due to the finite solubility Innovative Partnerships Program Office NASA Goddard Space Flight Center of the iron-nickel matrix and the extreme [email protected] sensitivity of the thermal expansion proper- http://ipp.gsfc.nasa.gov ties on the presence of unreacted elements
GSC-15158-1 04.15.08