Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 2601, Australia.
Physics, School of Science, RMIT University, Melbourne, Victoria 3001, Australia.
Phys Rev Lett. 2018 May 25;120(21):215701. doi: 10.1103/PhysRevLett.120.215701.
Glassy carbon is a technologically important material with isotropic properties that is nongraphitizing up to ∼3000 °C and displays complete or "superelastic" recovery from large compression. The pressure limit of these properties is not yet known. Here we use experiments and modeling to show permanent densification, and preferred orientation occurs in glassy carbon loaded to 45 GPa and above, where 45 GPa represents the limit to the superelastic and nongraphitizing properties of the material. The changes are explained by a transformation from its sp^{2} rich starting structure to a sp^{3} rich phase that reverts to fully sp^{2} bonded oriented graphite during pressure release.
玻璃碳是一种具有各向同性特性的重要技术材料，在高达约 3000°C 时不会石墨化，并能从大压缩中完全或“超弹性”恢复。目前还不知道这些特性的压力极限。在这里，我们通过实验和建模表明，在加载到 45GPa 及以上的玻璃碳中会发生永久致密化和择优取向，其中 45GPa 代表了材料超弹性和非石墨化特性的极限。这些变化可以通过从富含 sp^{2} 的初始结构向富含 sp^{3} 的相的转变来解释，在压力释放过程中，该相又恢复为完全 sp^{2}键合的取向石墨。
