The effect of preparation methods on the microstructure and dynamic compressive properties of 65W-25Cu-10Ni alloys

Two kinds of 65W-25Cu-10Ni alloys were prepared by spark plasma sintering (SPS) and liquid phase sintering (LPS) respectively. The effect of preparation methods on microstructure and dynamic compressive properties of the two alloys were investigated. The LPS-65W-25Cu-10Ni alloy has a larger tungsten grain size and better homogenization than SPS-65W-25Cu-10Ni alloy. Under dynamic compressive loading, the dynamic yield strength of SPS-65W-25Cu-10Ni alloy is 200 MPa higher than that of LPS-65W-25Cu-10Ni alloy. The failure strain of SPS-65W-25Cu-10Ni alloy is 0.58. While the specimen of LPS-65W-25Cu-10Ni alloy maintains integral even the strain reaches 0.62. The difference in dynamic property of the two alloys is attributed to the different preparation methods. Shorter sintering time of SPS impedes the growth of tungsten particle size in the alloy, which mainly accounts for the increase of yield strength. While the sintering condition of LPS process is beneficial for the homogenization of the matrix and the growth of tungsten particles, which results a better metallurgical bonding and deformation compatibility. The failure mechanism of SPS-65W-25Cu-10Ni alloy is also revealed. Under dynamic loading condition, the tearing of the matrix and cleavage of tungsten particles are main failure mechanisms of SPS-65W-25Cu-10Ni alloy.