Effect of Molybdenum Additions on Compaction during Sintering of Fine-Grained Iron-Copper Pseudoalloys

The effect of added molybdenum powder on compaction and the properties of sintered fine-grained iron-copper pseudoalloys is studied. The original powder mixtures are prepared by mechanical alloying, and the original powder particle size in mixtures does not exceed 0.5 μm. Specimens are sintered in the range 600-1130°C. It is shown that addition of molybdenum powder to the original charge accelerates compaction of fine pseudoalloys in both the solid phase and liquid-phase sintering compared with compaction of the same pseudoalloys without adding molybdenum. After solid-phase sintering the maximum relative density of specimens is 98.8%, and after liquid-phase sintering it is 99.3%. The main reasons for acceleration of compaction are prolonged retention of a fine-grained structure of sintered specimens up to the melting temperature for the phase based on copper and mutual diffusion between iron and molybdenum; to a significant extent the latter occurs during specimen heating in the solid phase.