Lattice strain of 1,3,5-triamino-2,4,6-trinitrobenzene-based polymer-bonded explosives during the pressing process by neutron diffraction

Pressed 1,3,5-triamino-2,4,6-trinitrobenzene (TATB)-based polymer-bonded explosives (PBXs) will undergo cracking under low-stress conditions, which are closely related to the TATB lattice strain. Studying the behavior of TATB lattice strain during the pressing process of TATB-based PBX is considered of great significance for revealing the causes and mechanisms of residual stress. In our research, neutron diffraction measurements were employed to study TATB lattice strain during the pressing process of typical TATB crystals and molding powders. In addition, the compressive load–displacement curve was utilized, alongside the microstructures through computed tomography (CT) and scanning electron microscopy (SEM). The results indicated that during the initial compression stage, the lattice strain of both typical TATB crystals and molding powders exhibited tensile behavior, demonstrating an increasing trend with applied load. Subsequently, as loading progressed, the lattice strain of the pure TATB crystals transitioned to compressive strain, characterized by two distinct phases of rapid and gradual decrease, while the lattice strain of the corresponding molding powders showed a linear decrease. Upon unloading of compressive stress, residual TATB lattice strain was observed, forming strain energy storage. The comprehensive evaluation of the pressing characteristics of the TATB molding powder with a bonding agent was found to be optimal.