Abstract
This report describes the results of investigations on the improvement of characteristics of tungsten heavy alloys which were produced with addition of suitable amount of Co (with Ni/Fe ratio of about 2.0) to basic composition of W-Ni-Fe, and an optimum amount of Co addition obtained. The mechanical properties at room temperature of the (91.8-93.4 wt% W) alloys increased with increasing Co content and attained a maximum with Co content of about 1.5 wt%, while the 95.4 wt% W alloys attained a maximum with Co content of about 0.5 wt%.
In the alloys with (addition of) suitable amount of Co, smaller dihedral angle between W-W grain and better "Wettability" were obtained, and it was made clear that those effect resulted in homogeneity of alloys, and the improved mechanical properties.
The SEM photographs of the fracture surfaces show that Co content alloys strengthen mainly the interface between W-binder phase boundaries and W-W grain boundaries.
