2004 Volume 68 Issue 7 Pages 419-426
In order to clarify the mechanism of rapid sintering including the densification and interparticle binding of ODS alloys during pulsed electric-current sintering (PECS) process, the micro-distribution of temperature in a sintered particle was analyzed by computer simulation based on the Joule's heating model combined with the heat conduction model. The temperature at the neck between sintered particles during PECS was compared with that during direct electric-current sintering (DECS) and hot-pressed sintering (HP). The temperature at the necked region was higher than the average temperature in a particle during PECS and DECS due to the concentration of electric-current at the neck. The temperature difference between the average temperature in a particle and the neck temperature was increased and attained the maximum of 235 K and 132 K for PECS and DECS of MA956 alloy and 225 K and 140 K for PECS and DECS of MA754 alloy, respectively, and then it was decreased with the lapse of heating time. The rise in temperature at the necked region was increased in the order of HP < DECS < PECS even at the same sintering condition. The rapid densification and interparticle binding in PECS of ODS alloys were dominantly attributed to the promotion of plastic-flow in a particle and the decomposition of oxide film at prior particle boundary by the local heat generation at the necked region.
