High temperature compression tests of a commercial isotropic ultrafine grain graphite

Graphite is often used to design components working at high temperature in a variety of industrial and research environments. It is therefore important to know the mechanical resistance of this material at high temperature. This work reports the compressive strength up to 2000 °C of an isotropic ultrafine grain graphite, the POCO EDM-3, which has not been analysed in the literature yet. This graphite is used to design components able to withstand extreme environmental conditions, due to the properties resulting from the uniform and isotropic microstructure of the material. A vacuum compression test equipment was developed, able to work above 2000 °C. Both cylindrical and hourglass-shaped specimens were tested and the influence of density was also evaluated. The influence of the materials in contact with the specimen ends was also analysed, but a negligible dependence was observed. The tests demonstrated that the compressive strength increases as the density and the temperature increase: at 2000 °C a 22% average increase of the compressive strength over its room-temperature value was noted.