Influence of Pressing Technique Parameters on Microstructures and Mechanical Properties of Polymer Bonded Energetic Materials

Powder compaction is the most widely used technology to fabricate polymer bonded explosives (PBX), and its parameters significantly influence the structures and mechanical properties of the final products. By conducting characterizations and experiments, this work performs a systematical study on the effects of compaction parameters. Cylindrical PBX samples are prepared with distinct fabrication parameters, including pressing rate, porosity factor, temperature and granular composition. Their initial micro-structures are obtained by scanning electron microscopy (SEM) and computer tomography (CT). The samples are tested with uniaxial compression experiments under strain rates varying from 0.0003 s⁻¹ to 7000 s⁻¹ to obtain the stress-strain responses. A rate-dependent nonlinear constitutive response model is established based on ZWT constitutive model, describing the mechanical response of the PBX samples. The recycled samples subjected to quasi-static compression are examined via SEM, and the deformation/damage mechanisms are revealed (intra-granular/inter-granular fractures and interfacial debonding). This work reveals the relations between the preparation parameters, material micro-structures and compressive properties. It provides abundant data of micro-structural characteristics and mechanical properties and proposes an efficient non-linear constitutive model for the PBX. The investigation is valuable for fabrication optimization and mechanical performance assessment of PBX.