Some Mechanical Properties of Graphite at Elevated Temperatures

Abstract

The short‐time tensile breaking strength of various grades of graphite was measured as a function of temperature from room temperature to the sublimation point. A characteristic common to all the strength versus temperature curves is that the strength approximately doubles in going from room temperature to about 2500°C and then decreases rapidly to zero near the sublimation point. Graphite can be used as a structural material at temperatures much higher than those permissible with other materials. The density distribution within an original block is given for grade EBP graphite. The creep characteristics of grade ECA graphite under tensile stress at elevated temperatures were investigated. The testing temperature ranged from 2200 to 2900°C while the applied stress varied from 500 to 5500 psi. The range of ``steady'' creep rates measured extended from 3×10−8 to 2×10−4 in. per in. per sec. The activation energy and change in entropy defined by rate theory were calculated for the above conditions. Low frequency dynamic measurements of the Young's modulus of grade ECA graphite made at temperatures from 1000 to 2000°C showed an increase of the modulus with temperature.