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: MgAl 2 O 4 for Al-0.3Mg, MgAl 2 O 4 + MgO for Al-1.0Mg, and MgO for Al-2.5, 10Mg alloys powders compacts.

Effect of Mg on the Sintering of Al-Mg Alloy Powders by Pulse Electric-Current Sintering Process

“…compositions of the crystalline particles depended on the amount of Mg addition in the alloys and sintering temperature, which are determined to be MgAl 2 O 4 or MgO, or both of them. Recently, we have reported the results at a sintering temperature of about 0.72 times as the solidus temperature for Al-Mg alloys 19) and those of Al-1.0 mass%Mg alloy at various sintering temperature. 20) Using the same analyses method, we have investigated the compositions of the crystalline particles on each Mg content and various sintering temperatures.…”

On tool stirring action in friction stir welding of work hardenable aluminium alloys

“…They concluded, in agreement with further researches, 16,17 that the zigzag line in the stir zone did not affect mechanical properties of the weld. Different studies, [17][18][19] conducted from the chemical point of view, reported that the amorphous Al 2 O 3 oxide in Al-Mg alloys easily changes into crystalline AlMg 2 O 4 or MgO phases during long time heating such as sintering and diffusion bonding. Therefore, there is a possibility that thermal cycle of FSW changes surface oxide layer from amorphous Al 2 O 3 to the crystalline phases.…”

Densification of Gas Atomized Ni-Based Metallic Glassy Powders by Spark Plasma Sintering

“…We have demonstrated that the tendency of change on the real density was consistent with the change of the apparent relative density. 25) It indicates that the observation of the linear shrinkage is very useful to understand the densification behavior of the powder compacts during the SPS process. Table 1 gives the measured relative density of the samples sintered by the SPS process at various sintering temperatures with a loading pressure of 600 MPa and a holding time of 10 min.…”