CHARACTERIZATION OF THERMALLY DEGRADED ENERGETIC MATERIALS

摘要

Characterization of the damage state of a thermally degraded energetic materialrn(EM) is a critical first step in understanding and predicting cookoff behavior.rnUnfortunately, the chemical and mechanical responses of heatedEMsare closelyrncoupled, especially if the EM is confined. We have examined several EMs inrnsmall-scale experiments (typically 200 mg) heated in both constant-volume andrnconstant-load configurations. Fixtures were designed to minimize free volumernand to contain gas pressures to several thousand psi. We measured mechanicalrnforces or displacements that correlated to thermal expansion, phase transitions,rnmaterial creep and gas pressurization as functions of temperature and soakrntime. In addition to these real-time measurements, samples were recovered forrnpostmortem examination, usually withscanning electron microscopy (SEM)rnand chemical analysis. We present results on EMs (HMX and TATB), withrnbinders (e.g., PBX 9501, PBX 9502, LX-14) and propellants (Al/AP/HTPB).