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Results of the analysis of experimental data on the conditions for initiation of explosive transformation in phlegmatized HMX samples on impact with an indenter with a spherical end are presented. It is shown that conditions for initiating explosive transformation in a wide range of variation of parameters of the indenter and impact velocities are described by empirical relationship that relate the mass-geometric parameters of an impactor with its minimum velocity, thereby initiating explosive transformation. The resulting relationships can be used for practically analyzing the outcomes of the influence on an explosive composition, constructing adequate physical initiation models, and verifying them.

In this paper, we present the experimental results of complex studies of the sensitivity to mechanical effects and detonation parameters of metalized explosive compositions based on weakly phlegmatized HMX and RDX. Powders of titanium, zirconium, and their hydrides and deuterides were used as fillers. The introduction of these components in an amount of up to 20 wt % is established to contribute to some increase in fire hazard and sensitivity of the compositions in handling them. Estimates show that an increase in the detonation parameters of the mixtures observed in some cases may be due to the chemical reactions of the additives with explosion products in the detonation wave front.

Recovery of explosives from obsolete ammunition has been considered an eco-friendly alternative to conventional dumping or detonation disposal methods Composition B, made of 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and paraffin wax, has been used as the main explosive filling in various munitions. It was selected as a model explosive for this study. TNT was extracted from Composition B by exploiting the different solubilities of TNT and RDX in acetonitrile. After removing paraffin wax by hexane washing, RDX was recovered from unused Composition B with a purity higher than 99% and a yield of 84%.

The investigations of new aluminum-enriched RDX-based composites belonging to the thermobaric and enhanced blast explosive formulations were undertaken. In a semi-closed bunker, the blast wave and the thermal characteristics of pressed and layered charges made from the composites are determined. The study includes the blast wave history registrations as well as the determination of the overpressure peaks and the specific impulses of the incident blast wave. The total impulses have been estimated for a period of 60 ms. Since the composites are supposed to be volumetric, the explosion light outputs and the fireball temperatures were also investigated. The results obtained for the composite charges were compared with the blast performances and fireball temperatures of TNT and phlegmatized RDX charges of the same mass. Also differences between the pressed and the layered composite charges prepared from the same composites were observed and explained. The effect of the aluminum particle size was checked. Discussion of the results and conclusions about the aluminum combustions during the explosions of such charges were presented.

We consider the physicomathematical formulation of the problem of explosive formation of a penetrator from a low-sphericity copper lining. Calculations are made for the formation of a penetrator for a phlegmatized hexogen charge for two models of the behavior of the lining material (copper), and the results are compared with the experimental data.

Conceptually new cylindrical charges enveloped by Al foils have been designed and their thermobaric effects, due to simultaneous fragmentation and combustion of the foils, have been experimentally determined. The fragmentation processes of Al foil was supported by numerical simulations. It has been shown that the quasistatic pressures (QSP) for phlegmatized RDX (RDX ph ) enveloped with Al-coated plastic foils are higher than that of the pure RDX ph , due to combustion of these foil fragments in a thermobaric explosion. The QSP generated by Al–Ni foils enveloping RDX ph was found to be much lower than performance of other foils, possibly due to relatively inert nature of Ni. In a small detonation chamber, the charges of RDX ph /Al foil (RDX ph /Alf) produced even higher experimental maximum peak pressure (Δ p max ) than the charges that contained Al powder (Al p ). In a closed bunker, the impulse amplitudes of RDX ph enveloped by aluminized polyethylene (Al-PE) foils and RDX ph enveloped by 100 µm Alf (Alf100) charges are much lower than those of the other charges. It was found that the charges enveloped by Al foils have even larger Δ p max than that of RDX ph /Al p charges, indicating that the Alf could generate better blast performances than the Al p . The simulations indicate that the observed blast enhancement is dependent not on the thickness, but on the size of surrounding space. The thermobaric fire-ball generated by 40 g RDX/Alf charge could sustain combustion up to 40 ms, reaching a maximum radius of about 2.4 m.

The confined explosion of an annular layered charge composed of a phlegmatized RDX (RDXph) core and an external layer consisting of aluminum powder (Al) or a mixture of ammonium perchlorate (AP) and Al was studied. Experiments were carried out in fully and partially closed structures, i.e., in the explosion chamber of 150 dm3 in volume and in the 40 m3 volume bunker with four small holes and a doorway. Two types of aluminum powder were used in the mixtures. Signals of overpressure from two piezoelectric gauges located at the chamber wall were recorded and the influence of aluminum contents and particle size on a quasi-static pressure (QSP) was studied. Moreover, the solid residues from the chamber were analyzed by using SEM, TG/DTA and XRD techniques to determine their structure and composition. Pressure and light histories recorded in the bunker enable us to determine the blast wave characteristics and time-duration of light output. The effect of the charge mass and aluminum particle size on blast wave parameters were investigated. For comparison, the test for RDXph and TNT charges were also carried out.

The applied pressure resulting in an explosion in the case of shock-induced shear is demonstrated to depend on the shear area [area of the contact of the high explosive (HE) with the metal surface]. The dependence of the probability of an explosion of the HE (phlegmatized HMX and PETN) compressed between two steel plates (end faces of two rollers) on the applied pressure and the contact area of the HE with the upper roller is confirmed in experiments on sensitivity to friction under shock-induced shear. The upper roller is shifted by 1.5 mm. It is demonstrated that an increase in the area of the shock-pressed HE contact with the roller increases the probability of the HE explosion under shock-induced shear of the upper roller at identical pressures applied to the HE. A scale factor of the influence of the HE/roller surface contact area on the pressure at which the HE explosion occurs under shock-induced shear of the surface contacting the HE is found. It is shown by statistical methods that the pressure leading to the HE explosion under shock-induced shear of the adjacent steel surface with respect to the HE is distributed in accordance with Weibull’s two-parameter law.

Phlegmatized FOX-7 (1,1-diamino-2,2-dinitroethylene, DADNE) and mixtures with cyclotetramethylene tetranitramine (HMX) were prepared and their detonation properties (the detonation velocity, detonation pressure, acceleration ability, and detonation energy) were investigated. The sensitivity of these compositions to mechanical stimuli (friction, impact, and shock wave) were determined, and the thermal stability and compatibility of the components were tested. This work furthers the investigation into new compositions for low vulnerability ammunition.

Проаналізовано причини підвищеного зношення внутрішньої поверхні артилерійських стволів. Розглянуто сучасні методики підвищення зносостійкості каналів стволів., К данном обзоре представлен список основных структурно-технологических методов предотвращения ускоренного сноса внутреннего канала артиллерийских стволов. Безусловно, основная причина сноса это выгорание металла внутренней поверхности ствола. Как основные методы предотвращения сноса стволов и их обновления указано: лейнерирование, наращивание металла, хромирование, антифрикционные смеси. Основной проблемой стала адаптация методов от смежных секторов промышленности, или образование синтетических методов основанных на сложном использовании части описанного в необходимых временных рамках, с наиболее эффективными материалами и в оптимальных количествах., To this review the list of basic structurally-technological methods of prevention of speed-up wear of internal channel of artillery barrels is driven. Certainly, that principal reason of wear is burning down of internal skim of metal without violation of form of barrel. The basic methods of prevention of wear of barrels and their renewal are indicated such as: laynering, increase of metal, chrome-plating, sheeting, anti-friction mixtures. Basic is a problem of adaptation of methods from contiguous industries, or formation of the synthetic methods based on the complex use of part of described in necessary terms, with the most suitable materials and with most effective.

Heats of explosion of non-ideal RDX-based compositions in four various atmospheres (argon, nitrogen, air and argon/oxygen mixture) were measured. Charges of phlegmatized RDX containing 30% of two types of aluminium powders, coarse aluminium oxide, or fine lithium fluoride particles were fired in a calorimetric bomb of 5.6 dm3 in volume. The influence of inert and reactive additives and the atmosphere filling the bomb on the heat outcome was examined. To estimate the degree of afterburning of the detonation products and reactive particles, thermochemical calculations were also performed for the tested explosive compositions.

The Zel’dovich theory predicts the possibility of realization of self-sustained weak detonation in systems with nonmonotonic energy release. The present paper describes experiments aimed at detecting such a regime of detonation in mixtures of phlegmatized RDX with PP-1 and PAP-2 aluminum powders. The mass fraction of aluminum was 20%. To examine the detonation regimes, 70-mm-in-diameter charges of these mixtures were initiated with powerful triangular pressure pulses, which gave rise to attenuating overdriven detonation waves. The pressure profiles were recorded at various distances from the initiation plane (from 10 to 80 mm). Specific features of the time evolution of the detonation wave profile indicative of the existence of a supersonic flow region arising not later than 0.15 μs behind the shock front were revealed. The supersonic character of the flow behind an intermediate C-J plane is an inherent characteristic of self-sustained weak detonation; i.e., direct experimental evidence for the existence of weak detonation in RDX-aluminum mixtures was obtained.

The mechanism of the effect of phlegmatizers in phlegmatized nitramines under mechanical loading is studied. Current concepts regarding the effect of phlegmatizers on the sensitivity of energetic materials to impact, friction, and vibration are considered; insufficiency of experimental data of this effect is noted. Experimental estimates of the phlegmatizing effect of various phlegmatizers on HMX are given.

Nonstandard and home-made explosives may constitute a considerable threat and as well as a potential material for terrorist activities. Mobile analytical devices, particularly Raman, or also FTIR spectrometers are used for the initial detection. Various sorts of phlegmatizers (moderants) to decrease sensitivity of explosives were tested, some kinds of low viscosity lubricants yielded very good results. If the character of the substance allows it, phlegmatized samples are taken in the amount of approx.0.3g for a laboratory analysis. Various separation methods and methods of concentrations of samples from post-blast scenes were tested. A wide range of methods is used for the laboratory analysis. XRD techniques capable of a direct phase identification of the crystalline substance, namely in mixtures, have highly proved themselves in practice for inorganic and organic phases. SEM-EDS/WDS methods are standardly employed for the inorganic phase. In analysing post-blast residues, there are very important techniques allowing analysis at the level of separate particles, not the overall composition in a mixed sample.

The investigations carried out in Military University of Technology on recovery and utilisation of explosives obtained from withdrawn munitions are reported. Commercial reapplication of recovered explosives for rock blasting in quarries is considered. Detonation characteristics of granulated TNT obtained during the process of melting down TNT-filled charges were investigated. Also performance of explosive mixtures obtained by introduction of nitrocellulose propellant into slurry and ANFO was examined. Positive results were obtained by applying granular TNT and phlegmatized hexogene for rock blasting. Also an application of crumbled or bunched nitrocellulose and nitro-glycerine propellants in quarrying was confirmed. TNT and RDX boosters as well as other work charges acquired from dismantled items were developed. Analyses as well as results of experimental registrations of detonation characteristics of explosive compositions of TNT and a component of positive oxygen balance (ammonium nitrate) are also presented.

This paper presents investigation data on changes in the sensitivity of HMX and the HMX‐based explosive compound (PBX‐9010 type) to the impact and friction when they are phlegmatized by the organic solvent such as dimethylformamide (DMF). For these types of exposure, the phlegmatized HMX and the explosive compound (EC) of PBX ‐9010 type are noted to have lower sensitivity, if compared with the initial HMX and EC of PBX ‐9010 type, respectively. The paper demonstrates the principle possibility to enhance explosion safety of damaged engineered systems (IS) due to the treatment of damaged EC parts, which are constituents of these systems, by organic solvents.

2-Oxo-1,3,5-trinitro-1,3,5-triazacyclohexane (Keto-RDX or K-6), the most powerful energetic material among nitrourea explosives, has been prepared and scaled up at laboratory level. The identity and purity of the product are tested by elemental analysis, IR, NMR, mass and HPLC techniques. Thermal response and sensitivity experiments on K-6 are also described. The data on sensitivity shows that K-6 can be utilised practically only in phlegmatized form.

This study sought to assign a rough order of magnitude for the amount of explosive residue likely to be available in real-world searches for clandestine explosives. A variety of explosives (TNT, TATP, HMX, AN, RDX, PETN) in various forms (powder, flake, detonating cord, plastic) were carefully weighed or cut into containers, and the amount of residue inadvertently remaining on the work area, hands, or containers was quantified. This was used to evaluate the spillage potential of each explosive. The adhesion of each explosive to a glass surface was quantified from amount of explosive adhering to the inside of a glass vial into which the explosive had been placed and then removed by vigorous tapping. In powdered form, most of the explosives--TNT, PETN, RDX, HMX, and TATP--exhibited similar spillage and adhesion to glass. However, PETN as sheet explosive and plasticized RDX (C-4), showed very little potential to contaminate surfaces, either by spillage or adhesion to glass.

WHEN a high explosive detonates, the measurement of the true emission of light from the detonation gases is of great interest. In air, however, the expanding detonation gas is enveloped in a compressed layer of the displaced air, which acquires a high temperature (c. 8,000° K. at atmospheric pressure) and emits an intense light. An easy way of eliminating the luminous layer of air is to immerse the charge in water. Charges of TNT and phlegmatized PETN, for example, then show a narrow luminous zone behind the detonation front. Fig. 1 shows instantaneous pictures (exposure time, 0.03 µsec.) of detonating cylinders of phlegmatized PETN of 1.55 gm./cm.3 density and 25-mm. diameter, first with (1a) then without (1b) background light of a detonated TNT-ball, (In Fig. 1b and Fig. 2 the upper end of the charge was above the surface.)