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DOE OSTI · 1735906

Preferred Void Orientation in Uniaxially Pressed PBX 9502

Mang, Joseph T.·Hjelm, Rex Paul Jr.
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Abstract

Ultra- and small-angle neutron scattering techniques were used to study the morphology of voids in directions parallel and perpendicular to the compaction plane of a uniaxially pressed cylinder of PBX 9502. Two-dimensional scattering patterns from samples cut parallel to the compaction plane had circular equal-intensity contours, implying that along this view the voids are circular or randomly oriented. Identical measurements of samples cut perpendicular to the compaction plane produced elliptical equal-intensity contours, indicating preferred orientation of voids. Analysis of the two dimensional scattering patterns confirmed that the voids are non-spherical with an average aspect ratio of 1.20, flattened so that the larger dimensions of the voids lie within the compaction plane. Model analysis of the combined ultra- and small-angle neutron scattering curves revealed that the PBX 9502 porosity is interconnected, in the form of aggregates comprised of non-spherical, primary voids. The volume dimension was found to be the same in both directions, indicating that the aggregate is randomly oriented throughout the sample, and that it is the primary voids that are preferentially oriented. Furthermore, void interfaces with the surrounding matrix were found to be rough or polydisperse, with a common roughness dimension or polydispersity in all directions.

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42 ENGINEERINGPBX 9502, anisotropy, porosity, fractal, SANS

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Mang, Joseph T., Hjelm, Rex Paul Jr.. 2020-12-03. Preferred Void Orientation in Uniaxially Pressed PBX 9502. https://doi.org/10.1002/prep.202000154

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