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Elastic materials with large reversible
deformation functions have a wide range of demands in a variety of engineering
applications. However, when the temperature decreases significantly, the
ductility or elasticity of the material is usually impaired. There is no
material that can achieve high elasticity at deep cryogenic temperatures such
as outer space so far.
Recently, Chen Yongsheng group, Nankai
University reported a three-dimensionally cross-linked graphene material with almost
unchanged ultra-elastic behavior over a wide temperature range from deep
cryogenic temperature (liquid helium, 4 K) to 1273 K. The mechanical properties
at 4K deep cryogenic temperature is almost the same as room temperature. They
share approximately completely reversible super elastic behavior (up to 90%
strain), unchanged Young's modulus, Poisson's ratio closing to 0, good cyclic
stability.
In situ experiments and simulations show
that this super elasticity benefits from the synergistic results of a unique
structure, which is based on the Eigen elasticity of a single graphene layer
and the covalent connection between the laminates.
Reference:
Kai Zhao*, Tengfei Zhang*,
Pulickel M. Ajayan† and Yongsheng Chen† et al. Super-elasticity of
three-dimensionally cross-linked graphene materials all the way to deep
cryogenic temperatures. Science Advances, 2019, 5, eaav2589
DOI: 10.1126/sciadv.aav2589
https://advances.sciencemag.org/content/5/4/eaav2589
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