Study on the relation between microstructural change and compressive creep stress of a PBX substitute material

Abstract A polymer-bonded explosive, also called PBX or plastic-bonded explosive, is an explosive material in which explosive powder is bound together in a matrix using small quantities (typically 5%–10% by weight) of a synthetic polymer. A PBX substitute material was made from sugar granules and polymer binder. Its compressive creep properties were investigated at room temperature. The creep deformation was found to depend strongly on the applied stress amplitude. Under an applied stress near the strength, creep deformation developed and reached the final rupture very quickly. A power law relationship, $\dot \varepsilon = 4.14 \times {10 ^{- 8}}{\sigma ^2.5},$ was established between steady creep rate and applied stress. Microscopic observations show that the damage mechanism processes include mainly the intergranular and transgranular fractures, binder fracture, and peeling. Both porosity and granule size decrease almost linearly with increasing applied stress.