Reduction of Surface Oxide Films in Al–Mg Alloy Powders by Pulse Electric Current Sintering

The reduction mechanism of particle surface oxide films on Al–Mg alloy specimens sintered by the pulse electric current sintering (PECS) process was investigated via transmission electron microscopy, energy dispersive x-ray spectroscopy, and thermodynamic calculation. The reduction products were either MgAl₂O₄or MgO or both, which is dependent on the sintering temperature and Mg content in Al–Mg alloy. Comparing the experimental temperature of the reduction products with that from thermodynamic calculation, it was suggested that the temperature at interfaces between particles was higher than that inside particles. This difference of temperature enhanced reduction of surface oxide films of Al–Mg alloy powders and hence accelerated the sintering in the PECS process.