Mechanical properties study of toughened and modified melt-cast TNT based explosive formulations for anti-cracks and brittleness

摘要

Melt-cast explosives often have poor mechanical properties and exhibit cracks, exudation, voids or brittleness. Especially, the exhibition of brittleness and cracks can affect the mechanical and detonation properties of melt-cast explosives based munitions, and restrain the application in high-performance weapon systems. Thus the defects in TNT based melt-cast explosive are analyzed The concept of "Toughening and Elasticizing of Melt-cast explosive" may become one of the directions in the study of melt-cast explosive, (ⅰ) research on the melt-cast explosives modifier mainly aiming at oil saturation and sensitivity reduction, in which the problem of brittleness and cracks has not been solved yet; (ⅱ) employ toughening techniques of other composites in the melt-casting process of composition B, such as toughening and elasticizing techniques of nanoparticles and polymer materials; (ⅲ)study the mechanical properties after blending and casting through designing and preparing the modifiers comparable to melt-cast explosives, start to establish the model and mechanism of toughening and elasticizing melt-cast explosives. Recent study of our group is introduced. Nanoindentation and scanning electron microscope (SEM) method were employed to analyze the brittleness of TNT, through indentation test of the large crystal of TNT and RDX, mechanical properties such as compressive modulus and stiffiness were calculated from load-deformation curves. The results indicated that indentation hardness and modulus of TNT are lower than RDX, while residual depth and maximum damage boundary of it were larger than RDX. Influence of additives (sulfide nitrile rubber, organic and inorganic fibers, etc.) on tensile strength, fracture strength and compressive intensity of composition B was investigated. It was shown that sulfide nitrile rubber nanoparticles have better effects on enhancing the elastic behavior of composition B, and glass fibers could reinforce the toughness.