MICROFRACTOGRAPHIC INVESTIGATION OF VISCOSITY IN SINTER CONTACT

In the upper temperature interval on heating to the isothermal sinteri ng temperature extraordinarily high rates of shrinkage are measured. T his can only be explained by the movement of whole powder particles in to the porosity voids. This type of material transport cannot however be observed in situ. In order to verify this, creep experiments were c arried out on sintering copper powder compacts under conditions of int ense shrinkage. The progressive stages of deformation up to complete s eparation of the disperse body were monitored by scanning electron mic roscopy. The results obtained support the assumption that the powder p articles slide into the voids on a low viscosity substance within the contact zone.