Engineers at Oak Ridge National Laboratory, Oak Ridge, Tenn., have succeeded in consolidating ground graphite foam ligaments in titanium powder to make disks up to 7 inches in diameter with bulk thermal conductivity of 240 W/m-K, as well as high strength. The ground ligaments are about 500 microns thick and range in length from 100 to 200 microns. Called Vari-k-Graphmet, the composite is currently consolidated by hot pressing; however, it has the potential for consolidation by additive manufacturing.
According to researcher Dr. Paul Menchhofer, graphite foam has thermal conductivity of 1700 w/m-K, which would enable a wide range of thermal management applications. However, the graphite foam is limited by its relatively low strength. Therefore, the team looked for ways to improve its strength, and this led to grinding the foam into ligaments and consolidating by hot pressing with titanium powder. Thermal conductivity can be tailored by changing both the amount and the size of the ground graphite foam ligaments. The composite has the potential to be low in cost, as both the graphite foam and the titanium powder are inexpensive.
The researchers are looking for partners in the titanium industry to optimize the graphite ligaments and the titanium powders, to scale up production, and to develop applications. Another goal is to make parts by additive manufacturing.
For more information, contact Paul Menchhofer at 865-576-5215, or [email protected].
