Sintering of mixtures of nickel-based prealloyed powders - A study of the homogenization and densification mechanisms

This research established the viability of processing alloys with complex compositions using mixtures of two prealloyed powders. The two powders were based on similar compositions, with differences in the distribution of certain alloying elements, such that the final composition was represented by the mixture. For demonstration experiments, two nickel-based alloys were used, with significant differences in melting points by incorporation of a melting point suppressant in one powder. Measurements of sintered density, composition, and phase evolution were used to determine the homogenization and densification mechanisms. Chemical homogenization was followed using electron microprobe analysis. A model describing the densification-homogenization kinetics was developed, which relies on the time-dependent rheological response during homogenization. This study isolates the key processing variables, including the effects of mixture composition, and sintering temperature.