Abstract
Various kinds of Al2O3-dispersion strengthened nickel powders were prepared by mechanical alloying process of carbonyl nickel powder (3μm in average particle size) with a-or γ-Al2O3 powder of about 100 nm each in particle size for various duration in the air atmosphere followed by heat-treatment in a hydrogen atmosphere at various temperatures, and sintera-bility of these powders was investigated.
It was found that the controlling factor which influenced the sintera-bility of oxide-dispersion strengthened nickel powders prepared by mechanical alloying process were the population and the thermal stability of the dislocations induced by mechanical alloying, and the interfacial energy between matrix and oxide which had a little direct contribution to the sinterability of these powders affected that indirectly through its influence on the thermal stability of the dislocations.
In Ni-Al2O3system γ-Al2O3-dispersed nickel powder was superior to α-Al2O3-dispersed one in the thermal stability of the dislocations and con-sequently in sinterability.
