Abstract
Al-PTFE (aluminum-polytetrafluoroethylene) serves as one among the most promising reactive materials (RMs). In this work, six types of Al-PTFE composites with different Al particle sizes (i.e., 50 nm, 1∼2 μm, 6∼7 μm, 12∼14 μm, 22∼24 μm, and 32∼34 μm) were prepared, and quasistatic compression and drop weight tests were conducted to characterize the mechanical properties and reaction characteristics of Al-PTFE composites. The reaction phenomenon and stress-strain curves were recorded by a high-speed camera and universal testing machine. The microstructure of selected specimens was anatomized through adopting a scanning electron microscope (SEM) to correlate the mesoscale structural characteristics to their macroproperties. As the results indicated, in the case of quasistatic compression, the strength of the composites was decreased (the yield strength falling from 22.7 MPa to 13.6 MPa and the hardening modulus declining from 33.3 MPa to 25 MPa) with the increase of the Al particle size. The toughness rose firstly and subsequently decreased and peaked as 116.42 MJ/m3 at 6∼7 μm. The reaction phenomenon occurred only in composites with the Al particle size less than 10 μm. In drop weight tests, six types of specimens were overall reacted. As the Al particle size rose, the ignition energy of the composites enhanced and the composites turned out to be more insensitive to reaction. In a lower strain rate range (10−2·s−1∼102·s−1), Al-PTFE specimens take on different mechanical properties and reaction characteristics in the case of different strain rates. The formation of circumferential open cracks is deemed as a prerequisite for Al-PTFE specimens to go through a reaction.
Highlights
Reactive materials (RMs), comprised of two or more nonexplosive solid components and known as impactinitiated energetic material, have aroused great attentions in recent years
It can be found that specimen #2 after sintering had much higher strength than that of before sintering. e difference of the strength was mainly attributed to the recrystallization of PTFE, which can be confirmed from the scanning electron microscope (SEM) photographs in Figures 3(a) and 3(b)
Six types of Al-PTFE specimens with different Al particle sizes were prepared, and their mechanical properties and reaction characteristics under quasistatic compression and dynamic impact were investigated. e main conclusions are as follows: (1) e stress-strain data under quasistatic compression show that the strength of the Al-PTFE specimen decreased with the increase of the Al particle size; the yield strength decreased from 22.7 MPa to 13.6 MPa; and the hardening modulus decreased from 33.3 MPa to 25 MPa
Summary
Reactive materials (RMs), comprised of two or more nonexplosive solid components and known as impactinitiated energetic material, have aroused great attentions in recent years. Polytetrafluoroethylene filled by aluminum particles (Al-PTFE) is one of the most promising RMs and has been studied extensively, owing to its easiness to deform and higher strength, stability, and energy density compared with traditional explosive [1,2,3]. When Al-PTFE is subjected to sufficiently strong mechanical stimulus, violent chemical reaction will occur with new substance produced and large amount of heat released In this regard, Al-PTFE takes on numerous prominent applications in military applications. Al-PTFE takes on numerous prominent applications in military applications It can be made into the warhead shell functionalized to cause secondary damage to increase the damage effect. It can be adopted in the systems of air defense, antimissile, obstacle breaking, and rocket propulsion [4]
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