抄録
The distribution of impurities (H, C, O, S, P, etc.) in the fracture surfaces of liquid sintered tungsten base composites has been measured by means of an Ion Microprobe Analyzer and also the mechanical properties have been investigate ?? .
Composites (91.3-95.5% W/5.8-3.0% Ni/2.9-1.5% Fe) were fabricated by the liquid phase sintering of powder (-2 μm) at 1460-1500°C in hydrogen atmosphere.
Three kinds of samples with different mechanical properties were analysed in terms of the amount of impurities in the tungsten grains, the binder phase and the interface between them.
Moreover, these materials were reheated at 1200°C for 9 hours in vacuo and at 850, 1050, 1250, and 1420°C for 6 hours in hydrogen atmosphere, respectively, and the impurities in the surfaces of these reheated test pieces were also analysed.
The existence of the impurities in the interface area was clarified. The mechanical properties were controlled by the strength of W-binder phase boundaries and W grain boundaries.
These findings support that the impurity segregation can be responsible for mechanical properties in the alloys.
