Effects of microstructure on mechanical and energy release properties of Ni–Al energetic structural materials

Ni–Al energetic structural materials (ESMs) has been widely applied in defense field, because of its good mechanical and energy release properties. The effects of the microstructure on mechanical and energy release properties of ESMs are not well understood. In this study, by designing the particle size Ni:Al = 1 μm:25 μm and Ni:Al = 20 μm:25 μm, two kinds of samples, Ni continuous phase (Nicp) and Al continuous phase (Alcp), were prepared by explosive consolidation. The microstructure characteristics were analyzed by scanning electron microscopy, electron backscatter diffraction, and transmission electron microscope. Quasi-static and dynamic compression tests were also conducted to analyze the mechanical properties. It showed that the Nicp ESMs had higher quasi-static compressive strength of 325 MPa and fracture strain of 21.3%, compared with the Alcp ESMs having the strength 275 MPa and the fracture strain 17.5%. Also, the dynamic compressive strength of the Nicp ESMs sample is higher than that of the Alcp ESMs sample. The reaction characteristics of the two ESMs in different atmospheres were discussed by differential scanning calorimetry. The result showed that the reaction temperature of the Nicp ESMs was lower. Impact-induced energy release tests on the two ESMs were performed to understand their energy release properties. The results showed that the microstructure had significant effects on the ignition velocity threshold and reaction efficiency. The Nicp ESMs has better reaction performance because of the high interface density.