Comparative study on microstructure and properties of different designed PTFE/Cu materials

Abstract

Polytetrafluoroethylene (PTFE)/Cu is an ideal low-density candidate preferred for energetic charge warheads, which can penetrate reactive armour without explosion. In this study, six types of modified PTFE with different Cu contents were produced using cold isostatic pressing (CIPing), followed by high-temperature sintering (CIPing + HTSing). The crystallinity and phase of the samples were analysed using X-ray Different phase analysis. The stress–strain curves of PTFE/Cu under dynamic impact were evaluated using split Hopkinson bar testing. Scanning electron microscope was used to characterise the microstructure of the PTFE/Cu, as well as to analyse the dynamic failure of the six samples. According to the results, sintering produces a new material (Cu2O) and increases the crystallinity of PTFE, thus strengthening the strength and plasticity of the PTFE/Cu composites. The strength of the CIPed + HTSed PTFE/Cu composites increased sharply at first, and then increased slightly with an increase in density, while the intensity of the CIPed PTFE/Cu samples increased with an increase in density. Therefore, sintering can improve the bonding strength of the PTFE and Cu interface. In addition, the thermal mismatch between PTFE and Cu indirectly enhances the properties of the composites. CIPed + HTSed PTFE/Cu composites enhance their properties by forming molecular chains internally, while the CIPed PTFE/Cu composite changes its properties by increasing its density. Therefore, the effect of the preparation technology on the mechanical properties is direct and significant than the density.