The mechanical behaviors of polytetrafluorethylene/Al/W energetic composites.

The tensile and impact properties of polytetrafluorethylene (PTFE)/Al/W reactive energetic composites were investigated using a universal materials testing machine and an improved pendulum impact tester at room temperature. Samples of four types, all containing W, of differing composition and particle size were prepared by cold pressing and sintering. With increasing W content in the PTFE/Al/W samples, the mass loss during sintering and the density of the materials obtained increased. The addition of microlevel W led to the tensile strength decreasing from 25.3 to 19.8 MPa, while the elongation changed little, but substituting nanolevel W for 5 wt% Al yields a maximal strength of 31.4 MPa. The failure behavior of PTFE/Al/W includes deformation, fracture, disorganization and reaction, in four steps. The addition of 30 wt% of coarse W particles improved the impact strength of the material, but the reactive activity increased and the perfectability of the reaction decreased.