Behavior of oxide film at interface between particles of Al-Mg alloy powder compacts prepared by pulse electric current sintering

Al-1.0mass% Mg alloy powders I were sintered using the pulse electric current sintering (PECS) process at various temperatures. The microstructure at the interfaces between powder particles and the effect of sintering temperature on interface characteristics were investigated using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The precipitates were,observed at the interfaces between powder particles of the compacts. The amounts of the precipitates increased and the compositions changed with an increase in sintering temperature: MgO for the compact sintered at 613 K, MgAl2O4+MgO for those at 663 K and 713 K, and MgAl2O4 for those above 763 K. Comparing the results obtained by-the PECS process with those of diffusion bonding experiments and thermodynamic calculation, it was suggested that the temperature at the interfaces between the particles was higher than that of the particles sintered, by the PECS process.