Sequential ultra-small-angle and small-angle and X-ray scattering (USAXS and SAXS) measurements of hierarchical microstructure of a common energetic material, the high explosive 2,4,6-Triamino-1,3,5-trinitrobenzene (TATB), were performed to follow the microstructure evolution upon applied pressure. The pellets were prepared by two different routes—die pressed from a nanoparticle form and a nano-network form of TATB powder. The derived structural parameters, such as void size, porosity, and the interface area, reflected the response of TATB under compaction. Three populations of voids were observed in the probed q range from 0.007 to 7 nm−1. The inter-granular voids with size larger than 50 nm were sensitive to low pressures and had a smooth interface with the TATB matrix. The inter-granular voids with size of ~10 nm exhibited a less volume-filling ratio at high pressures (>15 kN) as indicated by a decrease of the volume fractal exponent. The response of these structural parameters to external pressures implied that the main densification mechanisms under die compaction were the flow, fracture, and plastic deformation of the TATB granules. Compared to the nanoparticle TATB, the applied pressure strongly influenced the nano-network TATB due to its more uniform structure. The findings and research methods of this work provide insights into the structural evolution of TATB during densification.

中文翻译：

---

单轴模压下两种形式的纳米结构 TATB 的致密化：USAXS-SAXS 研究

对常见含能材料高爆炸药 2,4,6-三氨基-1,3,5-三硝基苯 (TATB) 的分级微观结构进行连续超小角度和小角度以及 X 射线散射（USAXS 和 SAXS）测量），以跟踪施加压力时微观结构的演变。这些颗粒是通过两种不同的途径制备的——由纳米颗粒形式和纳米网络形式的 TATB 粉末模压而成。导出的结构参数，如空隙尺寸、孔隙率和界面面积，反映了 TATB 在压实条件下的响应。在探测的 q 范围从 0.007 到 7 nm−1 内观察到三个空隙群。尺寸大于50 nm的晶间空隙对低压敏感，并且与TATB基质具有光滑的界面。尺寸约为 10 nm 的晶间空隙在高压 (>15 kN) 下表现出较小的体积填充率，如体积分形指数的降低所示。这些结构参数对外部压力的响应表明，模具压实下的主要致密化机制是 TATB 颗粒的流动、断裂和塑性变形。与纳米颗粒 TATB 相比，由于纳米网络 TATB 的结构更均匀，施加的压力对纳米网络 TATB 的影响很大。这项工作的发现和研究方法为致密化过程中 TATB 的结构演化提供了见解。