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. Void interfaces with the surrounding matrix were found to be rough or polydisperse, with a common roughness dimension or polydispersity in all directions.

中文翻译：

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单轴压制PBX 9502中的首选空隙方向

使用超小角度中子散射技术研究平行和垂直于PBX 9502单轴压制圆柱体压实平面方向上的空隙形态。平行于压实平面切割的样品的二维散射图样呈圆形强度相等的轮廓，这意味着沿此视图，空隙是圆形的或随机取向的。垂直于压实平面切割的样品的相同测量结果产生了椭圆形的等强度轮廓，表明了空隙的首选方向。二维散射图样的分析证实，空隙是非球形的，平均纵横比为1.20，已展平，因此较大尺寸的空隙位于压实平面内。对组合的超角和小角中子散射曲线的模型分析显示，PBX 9502孔隙度是相互联系的，形式是由非球形的主要空隙组成的聚集体。发现在两个方向上的体积尺寸是相同的，这表明聚集体在整个样品中是随机取向的，并且是主要空隙是优先取向的。发现与周围基质的空隙界面是粗糙的或多分散的，在所有方向上具有共同的粗糙度尺寸或多分散性。并且主要的空隙是优先定向的。发现与周围基质的空隙界面是粗糙的或多分散的，在所有方向上具有共同的粗糙度尺寸或多分散性。并且主要的空隙是优先定向的。发现与周围基质的空隙界面是粗糙的或多分散的，在所有方向上具有共同的粗糙度尺寸或多分散性。