Bulk Density Homogenization and Impact Initiation Characteristics of Porous PTFE/Al/W Reactive Materials

Geng, Baoqun; Wang, Haifu; Yu, Qian; Zheng, Yuanfeng; Ge, Chao

doi:10.3390/ma13102271

Cited by 14 publications

(8 citation statements)

References 33 publications

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“…As the MLR curves and experiment data described in Figure 12 , the dimensionless perforation diameters of the front plates decrease with the increasing projectile density at the same initial velocity. For the projectiles of a density lower than 4 g/cm 3 , due to the lower strength, less kinetic energy, and higher impact sensitivity characteristics [ 25 ], large deformation and violent deflagration occurred during perforating the plates, which make the front plate present petalling failure. Meanwhile, a longer perforation time enhances the deflagration expansion effect, and contributes to the perforation diameter for the low-density projectiles.…”

Section: Discussionmentioning

confidence: 99%

“…The flame radial distribution area on the plate surface is wider than that of the other types of projectiles as Figure 14 depicted. This is due to the high content PTFE matrix for the P1 projectile, which results in the characteristics of low dynamic strength and high sensitivity [ 5 , 25 ]. The projectile is easier to deform and react when it impacts the target plate, and the flame spreads a broader distribution area on the surface of the front plate.…”

Section: Discussionmentioning

confidence: 99%

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Perforation of Double-Spaced Aluminum Plates by Reactive Projectiles with Different Densities

Zhang

Wang

et al. 2021

Materials

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Perforation behavior of 3 mm/3 mm double-spaced aluminum plates by PTFE/Al/W (Polytetrafluoroethylene/Aluminum/Tungsten) reactive projectiles with densities ranging from 2.27 to 7.80 g/cm3 was studied experimentally and theoretically. Ballistic experiments show that the failure mode of the front plate transforms from petalling failure to plugging failure as projectile density increases. Theoretical prediction of the critical velocities for the reactive projectiles perforating the double-spaced plates is proposed, which is consistent with the experimental results and well represents the perforation performance of the projectiles. Dimensionless formulae for estimating the perforation diameter and deflection height of the front plates are obtained through dimensional analysis, indicating material density and strength are dominant factors to determine the perforation size. High-speed video sequences of the perforation process demonstrate that high-density reactive projectiles make greater damage to the rear plates because of the generation of projectile debris streams. Specifically, the maximum spray angle of the debris streams and the crater number in the debris concentration area of the rear plate both increase with the projectile density and initial velocity.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Perforation of Double-Spaced Aluminum Plates by Reactive Projectiles with Different Densities

Zhang

Wang

et al. 2021

Materials

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“…At the beginning, the initial porosity of a cell is,

where

is the theoretical density which is determined by the mass ratios of the components, and

is the actual density of the RM. According to Geng [ 28 ], the actual density of the RM prepared under the cold press-sintering process is related to the molding pressure and sintering temperature, and under ideal preparation conditions, the porosity of PTFE/AL (73.5/26.5) is about 5%. The collapse velocity of the spherical shell under uniform external pressure loading can be calculated as follows:

where

is the motion velocity of the localized material,

is the initial gas pressure in the pores,

is time,

is a delta function at

is a step function,

is the shear yield strength and

.…”

Section: Impact Ignition Behavior Of Rmmentioning

confidence: 99%

Theoretical Model for the Impact-Initiated Chemical Reaction of Al/PTFE Reactive Material

Liu

et al. 2022

Materials

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Reactive material (RM) is a special kind of energetic material that can react and release chemical energy under highly dynamic loads. However, its energy release behavior is limited by its own strength, showing unique unsustainable characteristics, which lack a theoretical description. In this paper, an impact-initiated chemical reaction model is proposed to describe the ignition and energy release behavior of Al/PTFE RM. The hotspot formation mechanism of pore collapse was first introduced to describe the decomposition process of PTFE. Material fragmentation and PTFE decomposition were used as ignition criteria. Then the reaction rate of the decomposition product with aluminum was calculated according to the gas-solid chemical reaction model. Finally, the reaction states of RM calculated by the model are compared and qualitatively consistent with the experimental results. The model provides insight into the thermal-mechanical-chemical responses and references for the numerical simulation of impact ignition and energy release behavior of RM.

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“…High-density powder additives such as tungsten (W), nickel (Ni), etc., increase density and strength [31,32]. It was shown in [33][34][35] that increasing the W and Ni content in the Al/PTFE mixture increases the strength of the composite but decreases the thermal effect of the reaction and the sensitivity to shock-wave initiation. The strength and shock-wave initiation of the Al/PTFE mixture is significantly affected by the particle size of initial powders.…”

Section: Introductionmentioning

confidence: 99%

Energetic Materials Based on W/PTFE/Al: Thermal and Shock-Wave Initiation of Exothermic Reactions

Saikov

Seropyan

Malakhov

et al. 2021

Metals

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The parameters of combustion synthesis and shock-wave initiation of reactive W/PTFE/Al compacts are investigated. Preliminary thermodynamic calculations showed the possibility of combustion of the W/PTFE/Al system at high adiabatic temperatures (up to 2776 °С) and a large proportion of condensed combustion products. The effect of the Al content (5, 10, 20, and 30 wt%) in the W/PTFE/Al system on the ignition and development of exothermic reactions was determined. Ignition temperatures and combustion rates were measured in argon, air, and rarefied air. A correlation between the gas medium, rate, and temperature of combustion was found. The shock initiation in W/PTFE/Al compacts with different Al content was examined. The extent of reaction in all compacts was studied by X-ray diffraction. The compositions with 10 and 20 wt% Al showed the highest completeness of synthesis after combustion and shock-wave initiation.

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Bulk Density Homogenization and Impact Initiation Characteristics of Porous PTFE/Al/W Reactive Materials

Cited by 14 publications

References 33 publications

Perforation of Double-Spaced Aluminum Plates by Reactive Projectiles with Different Densities

Perforation of Double-Spaced Aluminum Plates by Reactive Projectiles with Different Densities

Theoretical Model for the Impact-Initiated Chemical Reaction of Al/PTFE Reactive Material

Energetic Materials Based on W/PTFE/Al: Thermal and Shock-Wave Initiation of Exothermic Reactions

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