TATB造粒湍流涡传质及其颗粒热力响应行为研究

2,4,6-Triamino-1,3,5-trinitrobenzene (TATB) is currently the most important insensitive high explosive, and structural safety, detonation behavior and mechanical properties of TATB-based PBX (Polymer bonded explosive) have long been of interest in the field of energetic materials. As a complex aggregation of numerous TATB powder crystals, A TATB granule is the granular unit of PBX produced by warm compaction, which was affected by the turbulent flow during the granulation process. The underlying mechanism of different thermal/mechanical response emerged from the diversity of structures on the performance of PBX has been a long-standing puzzle. In this project, mass transfer involved in the preparation of TATB granules will be efficiently associated with the corresponding thermal/mechanical response and the role of turbulent flow in the mass transfer of TATB powder crystals and sub-microstructure of TATB granules will also be explored. A simultaneous scanning technique for combining X-ray nano/micro tomography with in-situ loading test over a wide temperature range will be developed, by which the evolvement of TATB granules under thermal/mechanical conditions, including their specific structures, interior pores, vortex rings and dense layers and so on, can be analyzed. Accordingly a quantitative characterization of the behaviors in three-dimension, such as structural deformation, pore evolution, density increment and dense layers toughness may be carried out, and the thermal/mechanical response model of TATB granules will be eventually established. These results may provide a meso-level theoretical and experimental basis to the significant demand of precision attack and structural mechanics.

TATB是目前安全性能最好的钝感炸药，围绕其成型的PBX结构安全性能、爆轰性能以及力学性能研究在国内外一直是热点。其中，一个TATB颗粒是由众多TATB粉末晶粘结聚集的复杂体系，又是温压成形PBX的颗粒物质单元，其形成不仅受造粒湍流作用并影响，其多样性结构不同热力响应行为对PBX性能的影响机理更是长期以来困扰的难题。本项目拟从纳/微尺度把造粒湍流涡传质（形成TATB颗粒）、TATB颗粒热力响应问题有机结合起来，研究流体对TATB粉末晶体传质及其造粒（亚）微结构的影响规律；发展一种X射线纳/微层析成像与原位宽温域力载同步扫描技术研究TATB颗粒及其颗粒体系内部孔隙、涡环层、致密层等热力演化规律，实现TATB颗粒结构变形、孔隙演变、密度递增、致密层韧性等特性三维定量表征，并建立TATB颗粒结构-热力响应模型，为解决武器对PBX精密爆轰稳定性、结构力学的重大需求问题研究提供细观理论与实验基础。

TATB是目前安全性能最好的钝感炸药，其中TATB造型颗粒是温压成形PBX的颗粒物质单元。TATB颗粒是由众多TATB粉末晶体粘结聚集的复杂体系，其形成不仅受造粒湍流作用并影响，其多样性结构不同热力响应行为对PBX性能的影响机理更是长期以来困扰的难题。本项目围绕TATB造型颗粒的成型过程、结构特征、力热行为规律等开展了一系列的研究工作。应用X射线微层析成像等多种微细结构表征技术，开展了TATB颗粒内部三维结构特征研究，分析获得了凝结涡旋环、致密表层的规律性认识，研究发现TATB颗粒内部存在0.1mm尺度的近椭球形凝结涡旋环，短长径比趋于0.7。自主设计了小型造粒装置在实验条件下模拟不同造粒流场，借助PIV等方法对造粒流场特性进行了表征，发现颗粒结构特征与雷诺数等流场参数存在关联。基于X射线微层析成像实验平台发展了适用于TATB颗粒、颗粒体系及其温压成形PBX的宽温域多尺度力学实验方法，并开展了力热行为的实验研究与分规律性析。首创性设计实现了微米-100mN级单轴压缩加载装置，获得了TATB颗粒压缩破坏过程的力学性质，研究发现内部结构较外形特征对颗粒力学性能影响更大。基于X射线微层析成像技术开展了TATB颗粒体系在温等静压过程的观测实验研究，分析压制后颗粒密堆形态、颗粒接触数、尺寸分布、界面特性、微杂质分布等，发现成型过程中轴向压力基本相同，径向压力则存在向轴心方向的压力降，基于离散元和力链方法建立了此过程的颗粒接触力学计算模型。开展了不同温度条件下TATB-PBX原位拉伸试验，运用形态学标记CT图像追踪典型颗粒运动历程，研究结果表明粘结剂对不同温度下的PBX的断裂特性和裂纹形态有重要影响。本项目围绕TATB颗粒结构，探究了造粒成因及其对材料力学性能的影响，发展了先进实验技术与方法、图像处理技术与方法等，丰富了TATB颗粒力学性质和实验数据，为TATB基PBX的重大需求问题研究提供了细观研究基础。