Researchers of the Lawrence Livermore National Laboratory’s (LLNL) additive manufacturing initiative have developed 3D printed materials that instead of expand, shrink when heated.
These 3D printed lightweight metamaterials can be tuned to shrink over a large range of temperatures. “This is a new version of a printing method we have developed and used in the past. We used it to create a thermomechanical metamaterial that may enable applications not possible before,” said Chris Spadaccini, director of LLNL’s Center for Engineered Materials and Manufacturing. “It has thermomechanical properties not achievable in conventional bulk materials.”
In the collaborative study with scientists from University of Southern California, MIT and the University of California, Los Angeles a bi-material micro lattice structure printed from polymer and a polymer/copper composite material that flexes inward was used. When exposed to heat over a range of tens to hundreds of degrees the structure contracts. The metamaterials could be used in applications for securing parts that tend to move out of alignment under varying heat loads such as microchips and high precision optical mounts.
“Traditionally, the way you compensate for (thermal mismatches) is with active control or heating and cooling,” Spadaccini explained. “But what if you could design a material that would hold the object and passively adjust to local temperature changes?”
The study was published in the October 21st edition of the Physical Review Letters journal.