Frontiers of Engineering Reports on Leading-Edge Engineering from the 2015 Symposium (2016) / Chapter Skim
Currently Skimming:
Materials by Design: Using Architecture and Nanomaterial Size Effects to Attain Unexplored Properties--Julia Greer
Materials by Design: Using Architecture and Nanomaterial Size Effects to Attain Unexplored Properties--Julia Greer
Pages 73-84
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 73... ...
The use of architectural features in defining multidimensional material design space will enable the independent manipulation of coupled physical attributes and the development of materials with unprecedented capabilities. The result is that the behavior and properties of architected structural metamaterials can no longer be defined solely by the properties of the constituent solid or by the structure or architecture; instead they benefit from the linked behavior of the material and the structure at very small dimensions.
|
From page 74... ...
Nanoarchitected structural metamaterials extend the concept of architecture to the micro- and nanometer length scale, often down to the atomistic level of material microstructure, enabling the use of material size effects to create metamaterials with amplified properties. Size effects that emerge in solids at the nanoscale -- single crystalline metals become stronger, nanocrystalline metals become weaker, and metallic glasses and ceramics undergo brittle-to-ductile transition (Greer and De Hosson 2011)
|
From page 75... ...
as relative density decreases. Relative densities of cellular solids, along with stiffness and strength, can be modulated by using hollow tubes instead of solid rods in the same architecture or by creating hierarchical structures (Figure 1)
|
From page 76... ...
. Hollow rigid nanolattices have recently attracted much interest as they attained GPa-level stiffnesses at ~10 percent of the density of the parent solid (Jang et al.
|
From page 77... ...
FIGURE 2 Computer-aided designs and scanning electron microscope images of fractal nanotrusses with various geometries specified above each set. Reprinted with permission from Meza et al.
|
From page 78... ...
Nanolattices were first fabricated from a negative photoresist (IP-Dip 780) using DLW TPL, which uses a 780 nm femtosecond FIGURE 3 A schematic of the two-photon lithography technique followed by the deposition of material of interest and etching out of the internal polymer scaffold.
|
From page 79... ...
Other Methods To make nanolattices out of different materials, the polymer scaffolds are coated (as conformally as possible) with the specific material of interest (e.g., metals, semiconductors, oxides, metallic glasses, piezoelectric materials, other polymers)
|
From page 80... ...
The ~10 nm thickness reduces the number and size of flaws in the Al2O3 -- the largest is only 10 nm! The combination of Weibull statistics flaw distribution-based fracture, a material size effect, and structural deformation mechanism as a function of (t/a)
|
From page 81... ...
Nanoarchitected metamaterials represent a new approach to "materials by design," making it possible to create materials with previously unattainable combinations of properties -- light weight and enhanced mechanical performance -- as well as unique thermal, optical, acoustic, and electronic attributes. Some realistic technological advances enabled by these metamaterials are untearable and unwettable paper, tunable filters and laser sources, tissue implants generated on
|
From page 82... ...
Acta Materialia 49:1035–1040. Deshpande VS, Fleck NA, Ashby MF.
|
From page 83... ...
Nature Photonics 2:52–56. Schaedler TA, Jacobsen AJ, Torrents A, Sorensen AE, Lian J, Greer JR, Valdevit L, Carter WB.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.