Effect of Compaction Temperature on Sinterability of Magnesium and Aluminum Powder Mixtures by Warm Compaction Method

Abstract

An oxide film is easily formed on the surface of magnesium and aluminum powders due to the high chemical reactivity of these metals. The sinterability of these powders is extremely poor for conventional powder metallurgy. At present, the behavior of the warm compaction method, which has been done using iron powder, is practically very interesting, because high density and strongly sintered materials are efficiently obtained. However, there are only a few reports on the sinterability of magnesium and aluminum powder mixtures by this method. In this study, to consider the sinterability of such mixtures, we examined the effect of the compaction temperature. The compacts that consist of these mixtures were consolidated by the warm compaction method, which was conducted in the temperature range from 301 to 423 K. The compacts were sintered in an argon atmosphere. As a result, the transverse rupture strength for the warm compaction was from 20 to 30 MPa higher than for the cold compaction. The increasing compaction temperature causes sufficient contact between the powder particles, and at the same time, plastic deformation of the powder particles readily occurs. This behavior induced by the warm compaction method would lead to a break down of the oxide films. As a result, sufficient bonding between the powder particles occurred, and the transverse rupture strength increased.

Simultaneous effects of strain rate and temperature on mechanical response of fabricated Mg–SiC nanocomposite

“…24 On the other hand, adding SiC particles increases hardness and strength of nanocomposite which leads to reduced relative compaction and increased porosity. 25 Iwaoka and Nakamura 26 stated that with the increase in compaction, porosity of samples decreases. As can be seen, by increasing the temperature from room temperature to 450 C, relative density for Mg-SiC samples with 10 vol.% of SiC increases by 2%.…”

“…Higher temperatures lead to disappearance of spaces between powder particles and full sintering. 26 This improvement can also be due to uniform distribution of reinforcing nanoparticles. 28 The improvement in microhardness can also be due to hardness of nanosized SiC-reinforcing particles, which limits the local deformation during compression (hardening effects of SiC nanoparticles).…”

Enhanced mechanical properties of carbon nanotube-reinforced magnesium composites with zirconia fabricated by spark plasma sintering

“…For comparison, the bending strength of Mg and Mg-1.15%(1at%)Sn-0.5%CNT2%ZrO 2 composites fabricated by SPS (in the current study), which are 243 and 269 MPa, respectively, are higher than that for Mg and Mg-12%Al fabricated by warm compaction method, which are 50-70 and 75-125 MPa, respectively. 36…”

Metal Scrap to Hydrogen: Manufacture of Hydroreactive Solid Shapes via Combination of Ball Milling, Cold Pressing, and Spark Plasma Sintering

“…Those phases were mostly located at the grain boundaries, but they were observed inside the grains as well in the form of well-distributed needle-shaped or round spots dozens of nanometers in size and decentralized speckles along the sub-grain boundaries. The predominating processes were disintegration of the Although it was likely that spark plasma sintering provided superior results over cold pressing, it would still be interesting to improve the compacting output of the latter technique by combining it with moderate heating up to 100-300 • C. Due to increased aluminum formability at elevated temperatures, such warm compacting techniques provided a higher density of the compacted samples [95][96][97]. It would be interesting to compare hydrogen generation performances (yield and evolution rate) for equal-sized samples manufactured using spark plasma sintering and warm compacting.…”