Preparation And Mechanical Properties Of W_f-Cu-Zn And W_f-W-Cu-Zn Composites

Firstly, the preparation process, mechanical properties and armor-piercing capability of Wf-Cu-Zn composites were studied in this paper. Then in order to improve the tungsten reinforced composites(TRC) ability to self-sharpen as the armor-piercing penetrator material, Wf-W-Cu-Zn composites were resigned. The preparation process, mechanical properties and failure mechanism under static and dynamic loading conditions of Wf-W-Cu-Zn composites were studied in this paper.Inverse infiltration process was used to prepare Wf-Cu-Zn and Wf-W-Cu-Zn composites. Optical microscopy(OM), scanning electron microscope(SEM) and energy dispersive spectroscopy(EDS) were occupied to analysis the microstructure of the composites and the composition of the binder phase. A static testing machine was employed to test the quasi-static compressive properties at normal temperature. Meanwhile, dynamic compression tests made by SHPB device were employed to test the dynamic compressive properties of the composites. Finally, the deformed and failure specimens were observed by OM and SEM.Through studying the influence of the infiltration temperature and holding time on microstructure and mechanical properties of the Wf-Cu-Zn, the preparation process is developed as: infiltration temperature is 1100 ℃, holding time is 4h. The strength of Wf-Cu-Zn under dynamic compression loading can reach 1900 MPa, and the critical failure strain can reach 0.14.When infiltration temperature increases from 1100 ℃ to 1200 ℃, the strength and critical failure strain of Wf-Cu-Zn under static and dynamic compressive loading increase; when holding time increases from 3h to 4h, the strength of Wf-Cu-Zn under static compressive loading and the critical failure strain of Wf-Cu-Zn under static and dynamic compressive loading increase, but the strength under dynamic compressive loading decreases.Under dynamic compressive loading, Wf-Cu-Zn is damaged like a drum. Firstly, tungsten wires were bent under the pressure of stress, which leads to separation of tungsten wires and binder phase. Then fracture of tungsten wires and binder phase in the central material occurs. Finally, fracture of Wf-Cu-Zn occurs. This failure mode is not conducive to the ability to self-sharpen of Wf-Cu-Zn.Compared with ordinary tungsten alloy, Wf-Cu-Zn has obvious advantages in armor-piercing performance. Under the same projectile velocity, Wf-Cu-Zn pierces deeper than the ordinary tungsten, increasing by 14.8%. The bullet made with Wf-Cu-Zn produces mushroom head during piercing process, and doesn’t show the ability to self-sharpen.The preparation process of Wf-W-Cu-Zn is developed as: infiltration once, diameter of tungsten wire is 0.15 mm. The strength of Wf-W-Cu-Zn under dynamic compression loading can reach 1500 MPa, and the critical failure strain can reach 0.22.Compared with Wf-W-Cu-Zn infiltrated twice, the strength and critical failure strain of composites infiltrated once under dynamic compression are higher, but the strength and critical failure strain under static compression are lower. Compared with coarse tungsten wires, the strength of Wf-W-Cu-Zn under dynamic and static compression and critical failure strain under static compression are higher, but the critical failure strain under dynamic is lower.Under dynamic compressive loading, the outer layer of Wf-W-Cu-Zn splits along the loading direction, and tungsten wires don’t have visible deformation. This special failure mechanism is beneficial to the improvement of the ability of Wf-W-Cu-Zn to self-sharpen.