Densification behavior of Fe, Co, and Ni powders with additions of zirconium, niobium, and molybdenum carbide powders

Summary

• 1. The densification behavior of Fe-ZrC, Fe-NbC, Fe-Mo₂C, Ni-ZrC, Ni-NbC,Ni-Mo₂C,Co-ZrC, Co-NbC, and Co-Mo₂C mixtures was investigated. It was observed that increasing the carbide content of mixtures intended for pressing raises their porosity at pressures above 10–15 kg/m² and lowers it at lower compaction pressures.

• 2. The dependence of the density of compacts on compaction pressure and carbide content was established. It was found that the magnitude n, which appears in Eq. (1), is a linear function of the amount of the second component over a wide range of carbide contents of a mixture. The magnitudes n₀ and K₀ in Eq. (4) are determined by the physicomechanical properties of the mixture components.

• 3. It was demonstrated that the presence of a lubricant (solution of synthetic rubber in benzine) exerts no significant influence on the value of n and on its rate of variation, i.e., on the value of K₀.

• 4. The effects of compaction pressure and the amount of a second component on compact porosity was studied. A hypothesis is advanced postulating that the same mechanism controls the deformation of sintered metal-powder materials and the deformation of powders subjected to densification in a closed die in the second stage of compaction.