Experimental Study on Impact‐induced Initiation Thresholds of Polytetrafluoroethylene/Aluminum Composite

Abstract

Impact experiments were conducted with a gas gun to investigate the impact-induced initiation thresholds of a polytetrafluoroethylene/aluminum (73.5 wt % and 26.5 wt %) composite. Targets of steel, aluminum, and lowdensity polyethylene materials and sample rods of four different lengths were used to decouple the effects of impact pressure and loading strain rate. By subjecting the samples to different loading conditions, it was shown that the impact-induced initiation of polytetrafluoroethylene/aluminum is decided by the impact pressure and the loading strain rate simultaneously. The impact pressure and strain-rate thresholds for initiation were arrested by the experiments. A 308 inclined steel target was used to produce a compression-shear configuration as a comparison with the normal impact experiments. The initiation was more likely to happen; it demonstrated a shear-induced initiation mechanism, and a lower initiation strain-rate threshold was observed under oblique impact. Based on the experimental results, two theoretical curves were proposed to predict the impact-induced initiation of polytetrafluoroethylene/aluminum under normal and 308 oblique impact.

Characterization of the Dynamic Response and Constitutive Behavior of PTFE/Al/W Reactive Materials

“…The PTFE/Al/W were prepared by a press/sintering process described in a previously published paper [4], and is briefly presented here. First, powders of Al (Hunan Goldsky Aluminum Industry High-Tech Co., Ltd., Changsha, China, JT-4), PTFE (DuPont PTFE 9002-84-0, type MP 1000) and W (Hunan Zhuzhou Jingzuan Co., Ltd., Zhuzhou, China) were mixed uniformly via a dry mixing process in vacuum, before a drying process at 50°C for~24 h. The dried mixtures were then prepressed under a pressure of 70~80 MPa, with a dwell time of approximately 10 minutes in a Φ20 × 10 mm steel mold.…”

“…Under intensive dynamic loading, plastic deformation and flow, or a fracture process caused intimate mixing of constituents results in a diffusion-controlled ignition of the material, and chemical reaction then happens between the Al particles and the PTFE matrix. Recently, research has been conducted into formulations and fabrications [2,3], impact initiation [4][5][6], chemical reaction [7,8] and energy release characteristics [9][10][11], by combining the methods of theoretical, numerical and experimental, to promote the understanding of reactive materials.…”

Reactive Structural Materials: Preparation and Characterization

“…A customized impact initiation testing methodology was developed a decade ago and modified and used in many more recent studies . In this method, as schematically shown in Figure , a consolidated RSM compact (which could have spherical, cylindrical, or cubic shape) is used as a projectile.…”

A comparative study on the mechanical and reactive behavior of three fluorine-containing thermites

“…Most importantly, PTFE can also be served as oxidant to react with Al and promote the energy release of thermite system. [23][24][25] Fluorine-containing thermite combines the characteristics of traditional thermite and metal/polymer reactive materials, and has distinct advantages compared with inert damage elements.…”