TEM Observation of Interfaces between Particles in Al-Mg Alloy Powder Compacts Prepared by Pulse Electric Current Sintering

Abstract

Aluminum–Magnesium (Al–Mg) alloys powders with various amounts of Mg addition were sintered using the pulse electric current sintering (PECS) process. The behavior of Mg in the surface oxide film and the effect of Mg amounts on characters of the interfaces between Al–Mg alloys powder particles were investigated using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The results showed that there were interfaces of direct metal/metal bonding and metal/oxide layer/metal bonding for all Al–Mg alloys powders compacts. In pure Al powder compacts, the oxide layer in the interface was amorphous alumina. And precipitates were observed in the bonding interface for the alloys powders compacts with Mg addition. The amounts of the precipitates increased, and the compositions of the precipitates changed with an increase in Mg amount in the alloys powders: MgAl₂O₄ for Al–0.3Mg, MgAl₂O₄+MgO for Al–1.0Mg, and MgO for Al–2.5, 10Mg alloys powders compacts.