3.3. Mechanical properties of the sintered composites
The hardness variation of samples with the Cu is illustrated in
Fig. 8. As seen in it, the hardness of the hard alloys is nearly
unchanged with the Cu content. This may be due to that the hardness
is mainly determined by the tungsten carbide phase in the
hard alloys [5,6]. The Cu distributes in the binder phase and has
no obvious effect on the tungsten carbide phase. Therefore, the
hardness changes little. However, the hardness decreases as the
temperature increases to 1350 C. When sintering temperature
increases, the microstructure turns coarser and coarser. It may
cause the hardness decreases [23]. This can be concluded that sintering temperature have more influence on the hardness than
Cu content.