The microstructure of a compressed explosive solid is closely related to its shock sensitivity and mechanical properties. In this study, ultra-small-angle and small-angle X-ray scattering (USAXS and SAXS) techniques were combined to explore the hierarchical microstructure of die-pressed 2,4,6-trinitro-1,3,5-benzenetriamine (TATB) discs obtained from nanostructured TATB (nano-TATB) powder as the precursor. Using the Guinier-Porod model, the pseudo-invariants, and Porod's law, this study analyzed the microstructures of the materials on a nanometer scale to track the changes in void size, porosity, and interfacial area, which reflected the response of TATB under applied pressures of 1, 2, 5, 10, 15 ​kN and 30 ​kN. Results show that there existed three populations of voids in the measured q range. The intergranular voids with sizes of tens of nanometers were sensitive to low pressures (<15 ​kN) and presented a smooth interface with the TATB matrix. The intragranular voids with sizes of 7–8 ​nm exhibited a fairly small volume-filling ratio under high pressures (>15 ​kN), as indicated by the decrease in the volume fractal dimension. Porosities of the voids with sizes of 1–900 ​nm, which were determined by the pseudo-invariants obtained from the scattering data, decreased from 6% to 1% as the pressures increased from 1 ​kN to 30 ​kN. The response of these structural parameters to external pressures implies that the main densification mechanisms under die compression include the flow, fracturing, and plastic deformation of the TATB granules. This study provides a direct insight into the structural evolution of TATB during compression.

压缩爆炸固体的微观结构与其冲击敏感性和力学性能密切相关。在本研究中，结合超小角和小角X射线散射（USAXS和SAXS）技术来探索模压2,4,6-三硝基-1,3,5-苯三胺的分级微观结构（ TATB）圆盘由纳米结构 TATB（纳米 TATB）粉末作为前体获得。本研究利用 Guinier-Porod 模型、伪不变量和 Porod 定律，在纳米尺度上分析材料的微观结构，以跟踪空隙尺寸、孔隙率和界面面积的变化，从而反映 TATB 在应用下的响应压力为 1、2、5、10、15 kN 和 30 kN。结果表明，在测量的q范围内存在三种孔隙群。尺寸为数十纳米的晶间空隙对低压（<15 kN）敏感，并与 TATB 基质呈现光滑的界面。尺寸为 7-8 nm 的晶内空隙在高压 (>15 kN) 下表现出相当小的体积填充比，如体积分形维数的降低所示。随着压力从 1 kN 增加到 30 kN，尺寸为 1–900 nm 的空隙的孔隙率（由从散射数据获得的伪不变量确定）从 6% 减少到 1%。这些结构参数对外部压力的响应意味着模具压缩下的主要致密化机制包括 TATB 颗粒的流动、破裂和塑性变形。这项研究提供了对 TATB 在压缩过程中结构演变的直接了解。