Indian Head Division Naval Surface Warfare Center

Indian Head, MD, United States

Indian Head Division Naval Surface Warfare Center

Indian Head, MD, United States
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Stoltz C.A.,Indian Head Division Naval Surface Warfare Center | Hooper J.P.,Indian Head Division Naval Surface Warfare Center | Mason B.P.,Indian Head Division Naval Surface Warfare Center | Roberts C.W.,Indian Head Division Naval Surface Warfare Center
Proceedings - 14th International Detonation Symposium, IDS 2010 | Year: 2010

We present the first small and ultra small angle neutron scattering (SANS/USANS) measurements of the internal void morphology of the high explosive RDX on length scales from 10 angstroms to 20 microns. Measurements were taken on a range of RDX samples with similar densities and particle size distributions, but which have significantly different sensitivities to shock initiation as measured by largescale gap tests. Scattering measurements were performed using a contrastmatch technique to eliminate all features apart from internal void structures. The dominant feature in all samples is a surface fractal scattering that extends from 50 nm to above 20 microns, with no observable upper bound for the fractal correlation length. These features are interpreted in terms of scattering from rough surfaces of interior airfilled voids with fractal dimensionality between 2.4 and 2.9. The fractal pattern is proposed to arise from complex growth patterns on void surfaces as internal solvent diffuses out of the crystallites. No evidence of distinct nanometerscale voids is observed in any of our RDX samples. The neutron scattering invariant calculated over the measured SANS and USANS range, a gauge of the volume fraction of voids smaller than 20 microns, tracks well with sensitivity testing of the materials. The results from these studies are compared to more traditional techniques, such as refractive indexmatched optical microscopy, BET surface area, and gas pycnometry density.


Gump J.C.,Indian Head Division Naval Surface Warfare Center | Stoltz C.A.,Indian Head Division Naval Surface Warfare Center | Mason B.P.,Indian Head Division Naval Surface Warfare Center | Freedman B.G.,Indian Head Division Naval Surface Warfare Center | And 5 more authors.
Journal of Applied Physics | Year: 2011

2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is an energetic ingredient that has an impact sensitivity close to that of TATB, yet a calculated energy content close to HMX. Reported tests of formulated LLM-105 reveal that it is a good candidate for a new insensitive high-performance explosive. As use of LLM-105 increases, thermodynamic parameters and phase stability will need to be determined for accurate modeling. In order to accomplish this goal, isothermal equations of state of LLM-105 at static high-pressure and temperature were investigated using synchrotron angle-dispersive x-ray diffraction and diamond anvil cells. Data at ambient temperature, 100°C (373 K), and 180°C (453 K) were used to obtain isothermal equations of state, and data at ambient pressure were used to obtain the volume thermal expansion coefficient. At ambient temperature, 100°C (373 K), and 180°C (453 K) no phase change was evident up to the highest measured pressure; and at ambient pressure, LLM-105 was stable up to 240°C (513 K) and thermally decomposed by 260°C (533 K). © 2011 American Institute of Physics.


Gump J.C.,Indian Head Division Naval Surface Warfare Center | Stoltz C.A.,Indian Head Division Naval Surface Warfare Center | Mason B.P.,Indian Head Division Naval Surface Warfare Center | Freedman B.G.,Naval Research Enterprise Intern Program | And 2 more authors.
Proceedings - 14th International Detonation Symposium, IDS 2010 | Year: 2010

2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is an energetic ingredient that has an impact sensitivity close to that of TATB, yet a calculated energy content close to HMX. Reported tests of formulated LLM-105 reveal that it is a good candidate for a new insensitive highperformance explosive. As use of LLM-105 increases, thermodynamic parameters and phase stability will need to be determined for accurate modeling. In order to accomplish this goal, isothermal equations of state of LLM-105 at static highpressure and temperature were investigated using synchrotron angledispersive xray diffraction experiments. The samples were compressed and heated using diamond anvil cells. Pressure - volume data for LLM-105 at ambient temperature, 100oC, and 180oC were fit to the BirchMurnaghan and Vinet equation of state formalisms to obtain isothermal equations of state. Temperature - volume data at ambient pressure were fit to obtain the volume thermal expansion coefficient. The thermal expansion coefficient was also determined for TATB from ambient pressure xray diffraction data. The diffraction patterns for TATB as a function of temperature were monitored to determine whether any hightemperature phase transitions occurred.

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