Fractal Networks of Inter-Granular Voids in Pressed TATB

Small‐angle neutron scattering techniques were used to study the evolution of void morphology with pressed density of the insensitive high explosive, TATB. Samples were studied as a loose powder and as pressed pellets, ranging in density from approx. 1 to 1.804 g cm−3. Inter‐granular voids in the loose powder were randomly arranged (non‐fractal) and had a surface defined mean size of 0.66 μm. Pressing was found to induce a fractal network of voids with fractally rough interfaces. The surface‐defined mean void size of the pressed samples was between 0.21–0.33 μm over the range of densities studied and was found to increase with pressed density up to 1.720 g cm−3, decreasing thereafter. The volume fractal dimension, indicative of the void arrangement, mirrored the changes in the mean void size. No systematic change in the surface fractal dimension was found. Surface area analysis allowed the average TATB grain size within the pressed samples to be quantified. An initial decrease of the mean grain size followed by an increase with pressed density suggests that the TATB grains behave in a brittle fashion at low densities and ductile at higher pressed densities.