Isothermal equations of state of beta octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine at high temperatures

Abstract

Isothermal pressure-volume equations of state of beta HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) at temperatures of 30, 100, and 140°C under both hydrostatic and nonhydrostatic compressions have been obtained using synchrotron angle-dispersive x-ray diffraction experiments. The samples were heated to the isotherm temperature and compressed up to 5.8GPa. At all temperatures HMX remained in the beta phase up to 5.8GPa. However, at 140°C upon decompression to ambient from nonhydrostatic pressures above 4GPa, HMX underwent a phase transition to the delta phase. The same transition was seen upon decompression to ambient from hydrostatic compression; however, parts of the sample remain in the β phase, resulting in a mixed-phase sample. The diffraction data were analyzed to yield unit-cell dimensions at each pressure, and further analyzed to yield thermal expansion, bulk modulus, and the pressure derivative of the bulk modulus.

Equations of state of unreacted explosives: PETN, RDX, HMX, TATB

“…Figures 11-15 show a comparison with experimental data from Refs. [8,9]. For the normal isotherm, calculations reproduce experimental data [8,9] (Fig.…”

“…[8], and rhombs are from Ref. [9]. The curves represent our calculations for two electron phases of HMX.…”

“…In this pressure range one can use experimental data presented in Refs. [8,9]. Reference [8] present data for the normal isotherm, and Ref.…”

“…Reference [8] present data for the normal isotherm, and Ref. [9] for the normal isotherm and isotherms of 100…”

Equations of state of hexanitrostilbene (HNS)

“…They also noted that the c-axis showed little compression throughout the entire simulated pressure range. Expansion of one of the unit cell axes under pressure has not been evidenced in similar compression experiments on other energetic materials [11,13,14].…”