Electric Current Activated Sintering of Porous Powder Compacts

A.Raychenko
 

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Omeliana Pritsaka str.,3, Kyiv, 03142, Ukraine
Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2015, #09/10
http://www.materials.kiev.ua/article/1994

Abstract

A powder body model has been developed to study the mass transfer through movement of the material as sliding blocks (packs) simulating particles and grains in polycrystals. The key parameters in the model are grain sizes and mobility of intergranular boundary layers. The theoretical analysis has resulted in mathematical relations showing that transfer of the material to fill the pores intensifies in transition to finer grains (subgrains, particles) and with higher mobility of material in the boundary layers between the grains. The boundaries between grains and particles experience increased heating during electric sintering. The temperature of the boundary zone remains higher than the area far from the boundaries, consequently leading to greater mobility of the material. This improves intergranular slip and promotes fast and ultrafast shrinkage.


INCREASED ELECTRIC HEATING OF INTERGRANULAR LAYERS, MOBILITY OF INTERGRANULAR LAYERS, SLIDING GRAINS (BLOCKS, PACKS)