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.
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