TATB 基炸药微结构精密表征及其力热响应基础问题研究

The microstructures of voids and interfaces in PBX explosive have a significant effect on the mechanical properties, sensitivities and detonation performances of explosives. The fine characterization of microstructures and the mechanism of association between the microstructures with the properties of explosives are of great significance for the theoretical development and practical application of high explosives. Based on the advanced neutron scattering technique and macro and micro numerical simulation methods, the present project will study the fine characterization of microstructures in the TATB-based PBX and their influences on the thermodynamic properties and mechanical properties of explosives. The neutron diffraction, diffraction and reflection techniques are also used to realize fine characterization of the grain orientation, the quantities and size distributions of voids. Taking advantages of the thermal loading and force loading techniques and neutron-situ testing techniques, the evolution process of the microstructures under various temperatures and pressures can be observed. The force field of TATB/additive interface and the high-order double-scale numerical method for the microstructure simulation of explosives are about to be developed. Based on the experimental data of microstructures, the explosive model will be constructed. Then the calculations of the macroscopic equivalent thermodynamic parameters of TATB-based PBX explosives and the numerical simulations of the thermal and mechanical responses of microstructure under thermal and force loading are realized. Through the combination of experiment and theory, the influence mechanism of microstructure on the thermodynamic properties, mechanical properties, and thermal and mechanical responses of the TATB-based explosives is revealed. The present project will provide a theoretical understanding for the improvement of the preparation process and the optimization of the storage conditions of explosives.

PBX炸药中孔洞、界面等微结构对炸药力学性能、感度和爆炸性能有显著影响。微结构的精密表征和与炸药性质关联机制研究，对于高能炸药理论发展和实际应用都具有重要的意义。本项目结合先进中子散射技术和宏、微观数值模拟方法，开展TATB基PBX炸药微结构精密表征和对炸药热力学性质的影响机制研究，综合利用中子小角散射、衍射和反射技术实现晶粒取向、孔洞尺寸和分布等微结构的定量表征，拟基于热力加载和中子原位测试技术，实现TATB基炸药微结构加载条件下演化过程的原位观测；发展TATB/添加剂界面力场和适用于炸药微结构模拟的高阶双尺度计算方法，基于微结构的实验表征构建炸药模型，实现TATB基PBX炸药的宏观等效热力学参数计算，实现热力加载条件下微结构动态响应数值模拟；实验与理论相结合，揭示微结构对TATB基炸药热力学性质和力热响应的影响机制，为炸药的制备工艺改进和贮存条件优化提供理论认识。

PBX炸药是当前武器和工程应用的一种关键的含能材料。PBX炸药组分多、结构复杂，在其制备过程中不可避免会引入微孔洞、位错、炸药-粘结剂界面等微结构缺陷,这些缺陷极大地影响炸药的热、力学性能和安全性。本项目开展TATB为基PBX炸药的微介观缺陷结构及其在力、热刺激下的响应研究工作，系统建立了PBX炸药微结构和界面结构的中子实验探测技术，包括：基于中子小角散射的孔洞尺寸分布、分形构特征、体积含量和孔洞比表面积的定量表征技术,实现对TATB粉晶颗粒和药片、TATB基PBX药片内部1nm至300nm孔洞尺寸的定量表征；基于中子衍射的TATB粉晶、TATB基PBX药片内部晶粒取向和体弹模量的定量表征技术；基于中子反射的HMX/氟橡胶双层膜界面扩散层厚度的定量表征技术。同时建立了微-宏观多尺度力学性能计算方法和TATB/氟聚物界面相互作用势。实验和数值模拟相结合，系统开展了TATB(HMX)/氟聚物炸药的微结构演化特征和粘结效应的数值模拟研究，首次提出一种新的温度相关PBX炸药缺陷演化机制；揭示了F2314与HMX界面混合相的存在，发现混合相对PBX炸药脱粘行为的影响机制；揭示了炸药内部的微孔洞在冲击加载下形成局部的滑移和压缩效应，导致局部形成高温区并产生热点；揭示了TATB炸药颗粒在压制过程中发生明显的塑性变形过程；揭示了随着TATB基PBX混合炸药随炸药晶粒增大其弹性模量逐步增大的主要机制。以上研究成果对于炸药制备工艺的提高、炸药的安全运输和存储具有十分重要的意义。相关成果目前已在在国内外核心期刊发表和接收发表论文18篇，取得授权发明专利3项。