AVERAGING TECHNIQUES IN POLYCRYSTALLINE GRAPHITES

The one-dimensional constant stress and constant strain models are used to calculate Young's moduli and coefficients of thermal expansion as a function of crystallite orientation in polycrystalline graphite. A previously proposed c-axis accommodation mechanism is introduced to approximate the microcracking occurring during cool-down from the graphitisation temperature. The constant stress model with accommodation is found to give the best agreement with the experimental values, but is shown to be inconsistent when porosity or a c-axis accommodation mechanism is considered. Two modified models are introduced which represent amalgamations of the one-dimensional constant stress and constant strain models. These modified models are shown to give good agreement with experiment and, in addition, give an insight into the anomalous behavior of polycrystalline graphite. © 1968.