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Starting at the nano-level Zheng has created hierarchical micro features across seven orders of magnitude , allowing the material to grow to a centimeter scale - allowing light weight , maximum strength , and super elasticity .
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Natural materials , such as trabecular bone and the toes of geckos , have evolved with multiple levels of 3-D architectures , spanning from the nanoscale to the macroscale . Human-made materials have yet to achieve this delicate control of structural features .
“ Creating 3-D hierarchical micro features across the entire seven orders of magnitude in structural bandwidth in products is unprecedented ,” said Zheng , the lead author of the study and the research team leader . “ Assembling nanoscale features into billets of materials through multi-leveled 3-D architectures , you begin to see a variety of programmed mechanical properties , such as minimal weight , maximum strength , and super elasticity at centimeter scales .”
The process Zheng ' s lab uses to create the material is an innovation in a digital light 3-D printing technique that overcomes current tradeoffs between high resolution and build volume , a major limitation in scalability of current 3-D printed microlattices and nanolattices .
Materials produced at the nanoscale , such as graphene sheets , can be 100 times stronger than steel , but trying to upsize these materials in three dimensions degrades their strength eight orders of magnitude — in other words , they become 100 million times less strong .
“ The increased elasticity and flexibility obtained through the new process and design come without incorporating soft polymers , thereby making the metallic materials suitable as flexible sensors and electronics in harsh environments , where chemical and temperature resistance are required ,” Zheng said .
These multi-leveled hierarchical lattice also means more surface area is available to collect photons ' energies , as they can enter the structure from all directions and be collected not just on the surface , like traditional photovoltaic panels , but also inside the lattice structure . One of the great opportunities this study creates is the ability to produce multi-functional inorganic materials , such as metals and ceramics , to explore photonic and energy-harvesting properties in these new materials
Besides Zheng , team members include Virginia Tech graduate research students Huachen Cui and Da Chen from Zheng ’ s group , and colleagues from Lawrence Livermore National Laboratory . The research was conducted under Department of Energy Lawrence Livermore Laboratory-directed research support with additional support from Virginia Tech , the SCHEV Fund from the commonwealth of Virginia , and the Defense Advanced Research Projects Agency .
Article - Rosaire Bushey