Simultaneous ultrasonic elastic wave velocity and in situ synchrotron X-ray measurements on grossular garnet were carried out up to 17 GPa and 1 650 K. P- and S-wave vdoeities and bulk and shear modulus showed linear ...Simultaneous ultrasonic elastic wave velocity and in situ synchrotron X-ray measurements on grossular garnet were carried out up to 17 GPa and 1 650 K. P- and S-wave vdoeities and bulk and shear modulus showed linear pressure and temperature dependence. These data yielded a pressure derivative of the bulk modulus of 4.42（7） and a shear modulus of 1.27（3）, which are in good agreement with those of garnets with variable chemical compositions. Temperature dependence of the bulk modulus of grossular （-1.36×10^-2 GPafK） is also similar to that of other garnets, while the temperature dependence of the shear modulus of grossular （-1.11×10^-2 GPa/K） is higher than those of magnesium end-member garnets and pyrolitic garnet.展开更多
Glassy carbon(GC)is a type of non-graphitizing disordered carbon material at ambient pressure and high temperatures,which has been widely used due to its excellent mechanical properties.Here we report the changes in t...Glassy carbon(GC)is a type of non-graphitizing disordered carbon material at ambient pressure and high temperatures,which has been widely used due to its excellent mechanical properties.Here we report the changes in the microstructure and mechanical properties of GC treated at high pressures(up to 5 GPa)and high temperatures.The formation of intermediate sp2-sp3 phases is identified at moderate treatment temperatures before the complete graphitization of GC,by analyzing synchrotron X-ray diffraction,Raman spectra,and transmission electron microscopy images.The intermediate metastable carbon materials exhibit superior mechanical properties with hardness reaching up to 10 GPa and compressive strength reaching as high as 2.5 GPa,nearly doubling those of raw GC,and improving elasticity and thermal stability.The synthesis pressure used in this study can be achieved in the industry on a commercial scale,enabling the scalable synthesis of this type of strong,hard,and elastic carbon materials.展开更多
基金supported by the research proposal to SPring-8 by Y Kono (No. 2007B1648)the Grant-in-Aid for Scientific Research from the Japanese Government to T Irifune
文摘Simultaneous ultrasonic elastic wave velocity and in situ synchrotron X-ray measurements on grossular garnet were carried out up to 17 GPa and 1 650 K. P- and S-wave vdoeities and bulk and shear modulus showed linear pressure and temperature dependence. These data yielded a pressure derivative of the bulk modulus of 4.42（7） and a shear modulus of 1.27（3）, which are in good agreement with those of garnets with variable chemical compositions. Temperature dependence of the bulk modulus of grossular （-1.36×10^-2 GPafK） is also similar to that of other garnets, while the temperature dependence of the shear modulus of grossular （-1.11×10^-2 GPa/K） is higher than those of magnesium end-member garnets and pyrolitic garnet.
基金supported by the National Key R&D Program of China(Grants No.2018YFA0703400)the National Natural Science Foundation of China(Grants Nos.51672238,91963203,51722209,and 51525205)+2 种基金M.Hu acknowledges fellowship support by the Alexander von Humboldt Foundation.Z.Zhao acknowledges 100 talents plan of Hebei Province(Grants No.E2016100013)NSF for Distinguished Young Scholars of Hebei Province of China(Grants No.E2018203349)K.Luo acknowledges the China Postdoctoral Science Foundation(Grants No.2017M620097).
文摘Glassy carbon(GC)is a type of non-graphitizing disordered carbon material at ambient pressure and high temperatures,which has been widely used due to its excellent mechanical properties.Here we report the changes in the microstructure and mechanical properties of GC treated at high pressures(up to 5 GPa)and high temperatures.The formation of intermediate sp2-sp3 phases is identified at moderate treatment temperatures before the complete graphitization of GC,by analyzing synchrotron X-ray diffraction,Raman spectra,and transmission electron microscopy images.The intermediate metastable carbon materials exhibit superior mechanical properties with hardness reaching up to 10 GPa and compressive strength reaching as high as 2.5 GPa,nearly doubling those of raw GC,and improving elasticity and thermal stability.The synthesis pressure used in this study can be achieved in the industry on a commercial scale,enabling the scalable synthesis of this type of strong,hard,and elastic carbon materials.
