Investigation on the Reaction Energy, Dynamic Mechanical Behaviors, and Impact-Induced Reaction Characteristics of PTFE/Al with Different TiH2 Percentages

Yu, Zhongshen; Fang, Xiang; Li, Yuchun; Wu, Jiaxiang; Wu, Shuangzhang; Zhang, Jun; Ren, Junkai; Zhong, Mingshou; Chen, Liping; Yao, Miao

doi:10.3390/ma11102008

Cited by 17 publications

(15 citation statements)

References 28 publications

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“…According to the main reaction equation of the material: 4Al + 3C 2 F 4 = 4AlF 3 + 6C, it can be seen that when TiH 2 is introduced into Al-rich Al/PTFE (wt50%/wt50%) active material, the maximum content of TiH 2 is 32%. According to the reference [ 20 , 21 ], the Al/PTFE/TiH 2 active material with TiH 2 content of 10% has moderate energy release rate and reaction threshold. Therefore, In this paper, Al (wt40%)/PTFE (wt50%)/TiH 2 (wt10%) was selected as the composition of 10 groups of specimens.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, Yu [ 20 , 21 ] introduced TiH 2 into Al/PTFE energetic materials for the first time under zero oxygen balance, and mainly aimed to analyze the effect of different TiH 2 content on the static mechanical properties of Al/PTFE/TiH 2 composites under equilibrium condition. Through quasi-static compression experiments, the effects of different content of TiH 2 on the mechanical properties and reaction characteristics of Al/PTFE were compared and analyzed.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Molding Parameters on Quasi-Static Mechanical Properties of Al-Rich Al/PTFE/TiH2 Active Materials

Wang

Jiang

2021

Materials

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Preforming pressure and the pressure holding time are important parameters of the molding process, which directly affect the mechanical properties of materials. In order to obtain the best molding parameters of Al-rich Al/PTFE/TiH2 composites, based on the quasi-static compression test, the influence of molding parameters on the mechanical properties of Al-rich Al/PTFE/TiH2 composites was analyzed, and the microstructure characteristics of Al-rich Al/PTFE/TiH2 specimens were analyzed by SEM. An X-ray diffractometer was used to analyze the phase of the residue after quasi-static compression experiment. The results show that: (1) With the increase in molding parameters (preforming pressure and the pressure holding time), the compressive strength, failure strain and toughness of Al-rich Al/PTFE/TiH2 specimens first increase and then decrease. The best molding process parameters of Al-rich Al/PTFE/TiH2 materials are preforming pressure 240 MPa and the pressure holding time 100 s. (2) For unsintering specimens, when the preforming pressure is less than 150 MPa, the porosity of the specimen increases slowly at first and then decreases. When the preforming pressure is greater than 150 MPa, the porosity of the specimen increases first and then decreases. When the pressure holding time is no more than 100 s, the porosity of the specimen decreases gradually. When the pressure holding time is more than 100 s, the porosity of the specimen increases first and then decreases. For sintered specimens, when the preforming pressure is less than 100 MPa, the porosity of the specimen decreases gradually. When the preforming pressure is greater than 100 MPa, the porosity of the specimen first increases and then decreases. With the increase in the pressure holding time, the porosity first increases and then decreases. For each preforming pressure specimen, compared with that before sintering, the porosity after sintering either decreases or increases. For each the pressure holding time specimen, the porosity increases after sintering compared with that before sintering. The microstructure of PTFE crystal inside the specimen is mainly planar PTFE crystal. The size and number of planar PTFE crystals are significantly affected by the molding parameters, which further affects the mechanical properties of Al-rich Al/PTFE/TiH2 specimens. When the preforming pressure is less than 100 MPa, the planar PTFE crystals are small and few, which results in the worst mechanical properties of the specimens. When the preforming pressure is more than 100 MPa and does not contain 240 Mpa, the planar PTFE crystals are small and there are more of them, which results in better mechanical properties of the specimens. When the preforming pressure is 240 MPa, the planar PTFE crystals are large and numerous, which results in the best mechanical properties of the specimen. When the pressure holding time is 100 s, the planar PTFE crystals are large and there are more of them, which results in the best mechanical properties of the specimen. (3) The reactivity of Al-rich Al/PTFE/TiH2 specimens with TiH2 the content of 10% under quasi-static compression is not significantly affected by the molding parameters.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Molding Parameters on Quasi-Static Mechanical Properties of Al-Rich Al/PTFE/TiH2 Active Materials

Wang

Jiang

2021

Materials

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“…Following this, severe reaction decreases gradually, and the range of the reaction cluster shrinks and sparks sputter around in the complete reaction zone. PTFE based reactive materials initiated unstably under low-speed impact [15,[30][31][32]. That is, the reactive materials could be initiated to form a violent reaction, or it might perform like inert material in identical impact circumstances.…”

Section: Effect Of Tmdmentioning

confidence: 99%

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

Geng

Wang

et al. 2020

Materials

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In this research, the bulk density homogenization and impact initiation characteristics of porous PTFE/Al/W reactive materials were investigated. Cold isostatic pressed (CIPed) and hot temperature sintered (HTSed) PTFE/Al/W reactive materials of five different theoretical maximum densities were fabricated via the mixing/pressing/sintering process. Mesoscale structure characteristics of the materials fabricated under different molding pressures were compared while the effect of molding pressures on material bulk densities was analyzed as well. By using the drop weight testing system, effects of the theoretical maximum densities (TMDs), drop heights and molding pressures on the impact initiation characteristics were studied. Quantitatively, characteristic drop heights (H50) for different types of materials were obtained. The two most significant findings of this research are the density homogenization zone and the sensitivity transition zone, which would provide meaningful guides for further design and fabrication of reactive materials.

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“…Therefore, one of the biggest problems with PTFE/Al reactive materials is that the energy release efficiency is too low. Some researchers considered adding materials such as Fe 2 O 3 , Mg, TiH 2 , or MnO 2 [20][21][22][23][24]. These materials react more readily with Al or PTFE and release a large amount of heat, which promotes the reaction of PTFE/Al.…”

mentioning

confidence: 99%

“…Scanning electron microscopy, a universal material testing machine, a Split Hopkinson pressure bar (SHPB) device, and a drop hammer device were used to test and analyze the PTFE/Al/CuO reactive materials. These test methods are commonly used to test reactive materials [5,15,16,23]. Scanning electron microscopy was used to observe the microstructure of the reactive material.…”

mentioning

confidence: 99%

Experimental Study of Mechanical Properties and Impact-Induced Reaction Characteristics of PTFE/Al/CuO Reactive Materials

2019

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Metal/fluoropolymer materials are typical reactive materials. Polytetrafluoroethylene (PTFE)/Al/CuO reactive materials were studied in this research. Scanning electron microscopy (SEM), quasi-static compression, the Split Hopkinson pressure bar test, and the drop hammer test were used to study the mechanical properties and induced reaction characteristics of the reactive materials with different Al/CuO thermite contents and different particle sizes. SEM images of the samples demonstrate that the reactive materials were mixed evenly. The compression test results show that, if the particle size of PTFE was too small, the strength of reactive materials after sintering was reduced. After sintering, with the increase in the content of Al/CuO thermite, the strength of the micro-sized PTFE/Al/CuO firstly increased and then decreased. The Johnson-Cook constitutive model can be used to characterize the reactive materials, and the parameters of the Johnson-Cook constitutive model of No. 3 reactive materials (PTFE/Al:Al/CuO = 3:1) were obtained. The reliability of the parameters was verified by numerical simulation. Drop hammer tests show that the addition of Al/CuO aluminothermic materials or the use of nano-sized PTFE/Al reactive materials can significantly improve the sensitivity of the material. The research in this paper can provide a reference for the preparation, transportation, storage, and application of reactive materials.found that adding a high-strength metal material, such as W, with a similar particle size to the PTFE/Al reactive material, can effectively increase the strength of the reactive materials. Cai et al. [12] used a drop hammer to find that the W particle-PTFE interface separation provided initiation and propagation of cracks. In general, the addition of W can increase the strength of the reactive material but reduce the energy density. Thus, people considered adding materials that can release energy, such as Ni. After adding Ni to PTFE/Al, Wu et al. [16] found that Ni makes the reactive material brittle, but it can increase the strain-hardening modulus and compressive strength of the material, while the heat released by the material also increased. However, the energy density of PTFE/Al reactive material is very high, and the energy of PTFE/Al reactive material cannot be significantly increased by adding Ni. If the energy release efficiency of the PTFE reactive materials can be effectively improved, it will be beneficial for their application. PTFE filler metal is a very common type of engineering material. The C-F bonds in PTFE are usually stable and do not react with metals. Under high-temperature conditions, PTFE rapidly decomposes into small-molecule fluorides and undergoes a rapid exothermic reaction with active metals [18]. Experiments by Ames [19] showed that, when the PTFE/Al reactive material impacts the target at a velocity of 1.2 km/s, the energy release efficiency still does not exceed 20%. Therefore, one of the biggest problems with PTFE/Al reactive materials is that the energy release ...

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Investigation on the Reaction Energy, Dynamic Mechanical Behaviors, and Impact-Induced Reaction Characteristics of PTFE/Al with Different TiH2 Percentages

Cited by 17 publications

References 28 publications

Influence of Molding Parameters on Quasi-Static Mechanical Properties of Al-Rich Al/PTFE/TiH2 Active Materials

Influence of Molding Parameters on Quasi-Static Mechanical Properties of Al-Rich Al/PTFE/TiH2 Active Materials

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

Experimental Study of Mechanical Properties and Impact-Induced Reaction Characteristics of PTFE/Al/CuO Reactive Materials

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