Acceleration of delta- to beta-HMX-D8 Phase Retransformation with D2O and Intergranular Strain Evolution in a HMX-Based Polymer-Bonded Explosive

摘要

Octahydro-1,3,5;7-tetranitro-1,3,5,7-tetrazocine (HMX) is one of the most widely used explosives. Problems about phase state and unrecoverable damage are significant in the application of HMX and HMX-based polymer-bonded explosive (PBX). Recently, the acceleration of delta- to beta-HMX retransformation in humid atmosphere was reported. However, the function of water was not well understood. In this paper, we studied the mixed phase during delta- to beta-HMX-d8 retransformation with neutron diffraction. Evidence of gamma-HMX-d8 is specially focused to estimate whether the hydrated phase is part of the delta- to beta- phase retransformation. Besides, in situ high-pressure neutron diffraction of HMX-based PBX was performed to study the evolution of intergranular strains in special structures such as twin plane, cleavage planes, and slip systems. We observed an abnormal release of strain on certain planes under applied pressure which had not been reported. This abnormal phenomenon was considered to explain the formation of microcracks in HMX.