Investigation on the Thermal Behavior, Mechanical Properties and Reaction Characteristics of Al-PTFE Composites Enhanced by Ni Particle

Abstract

Al-PTFE (aluminum-polytetrafluoroethene) is regarded as one of the most promising reactive materials (RMs). In this work, Ni (Nickel) was added to Al-PTFE composites for the purpose of improving the energy density and damage effect. To investigate the thermal behavior, mechanical properties and reaction characteristics of the Al-Ni-PTFE composites, an Al-PTFE mixture and an Al-Ni mixture were prepared by ultrasonic mixing. Six types of Al-Ni-PTFE specimens with different component mass ratios were prepared by molding sintering. Simultaneous thermal analysis experiments were carried out to characterize the thermal behavior of the Al-PTFE mixture and the Al-Ni mixture. Quasi-static compression tests were performed to analyze the mechanical properties and reaction characteristics of the Al-Ni-PTFE specimens. The results indicate that the reaction onset temperature of Al-Ni (582.7 °C) was similar to that of Al-PTFE (587.6 °C) and that the reaction heat of Al-Ni (991.9 J/g) was 12.5 times higher than that of Al-PTFE (79.6 J/g). With the increase of Ni content, the material changed from ductile to brittle and the strain hardening modulus and compressive strength rose first and then subsequently decreased, reaching a maximum of 51.35 MPa and 111.41 MPa respectively when the volume fraction of Ni was 10%. An exothermic reaction occurred for the specimens with a Ni volume fraction no more than 10% under quasi-static compression, accompanied by the formation of Ni-Al intermetallic compounds. In the Al-Ni-PTFE system, the reaction between Al and PTFE preceded the reaction between Al and Ni and the feasibility of increasing the energy density and damage effect of the Al-Ni-PTFE reactive material by means of Ni-Al reaction was proved.

New Functional Materials in Mechanical Engineering and Geology

“…The thermal behavior, mechanical properties, and reaction characteristics of Al/Ni/PTFE composites were studied in [20]. A result of quasi-static compression tests showed that the heat of reaction of Al-Ni was 12.5 higher than in the Al-Ni-PTFE system.…”

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

“…Among the metal/fluoropolymer reactive materials, the PTFE/Al composite is the most studied. Since it was found that the density of PTFE reactive materials is low and their strength is not sufficient, many researchers tried increasing the strength of PTFE/Al by adding W or Ni elements [10][11][12][13][14][15][16][17] (2) Uniform mixing of powders. The main raw materials for reactive materials in this paper included Al (10 µm and 50 nm), PTFE (35 µm and 350 nm), and CuO (50 nm) powders, as shown in Table 2.…”

“…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.…”

“…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.…”

Sintering Reaction and Pyrolysis Process Analysis of Al/Ta/PTFE

“…Although Al/PTFE reactive materials have higher strength and density than traditional energetic materials, there are still many problems to be solved in practical applications, such as inferior strength to metal components, insufficient penetration ability as a warhead; insufficient energy release level, as well as testing and research of constitutive relations of reactive materials. Some scholars have introduced metals (W, Ni) [13,14,15], metal oxides (Fe 2 O 3 , CuO 2 ) [16,17], and metal hydrides (TiH 2 ) [18] in Al/PTFE, with the aim of improving the mechanical properties or energy release rates of Al/PTFE reactive materials, on which much research has been conducted. Metal Ta is a kind of transition metal with high-density (16.65 g/cm 3 ) [19] and high hardness (6.5) [20], which is much larger than that of Al (density is 2.7 g/cm 3 and hardness is 2–2.9), and it has good heat transference, fracture toughness and corrosion resistance within a wide temperature range.…”