Microstructure and Mechanical Properties of Al–SiC Nanocomposites Synthesized by Surface-Modified Aluminium Powder

Abstract

Ceramic nanoparticle-reinforced aluminium metal matrix composites (AMMCs) have superior mechanical properties compared with matrix alloys, exhibiting great potential in structural applications in industries such as the aerospace and automotive sectors. This research proposes a new method for distributing SiC nanoparticles in an aluminium matrix alloy by powder metallurgy. The mixing of aluminium powder and SiC nanoparticles was processed by a two-step procedure, which included ultrasound-assisted stirring and planetary agitation. After that, the mixing powder was subjected to compaction, sintering and extrusion. A blank sample and three composite sheets containing 1, 2 and 3 wt % SiC nanoparticles were prepared and the mechanical properties were investigated by micro-hardness and tensile tests. A scanning electron microscope (SEM) and electron back-scattered diffraction (EBSD) were used for microstructural analysis of the composite. Experimental results revealed that by adding 1, 2, 3 wt % SiC nanoparticles, hardness was increased by 26%, 34.5%, 40.0% and tensile strength was increased by 22.3%, 28.6% and 29.3%, respectively. The grain size of the aluminium matrix decreased with the addition of SiC nanoparticles. Moreover, a decrease of elongation was observed with the increasing weight fraction of SiC.

A Review on Nanocomposites. Part 1: Mechanical Properties

“…This part of the review will be the basis to analyse the machinability of nanocomposites when employing mechanical micromachining techniques where the mechanical properies will be correlated with different machining measures. Table 1 Nanocomposite manufacturing techniques Table 2 Nano-filler geometries Table 3 Fracture toughness of polymer reinforced CNT nanocomposites with the consideration of various factors Table 4 Mechanical properties of CNT reinforced metal matrix nanocomposites Table 5 Mechanical properties of graphene reinforced polymer matrix nanocomposites Table 6 Mechanical properties of graphene reinforced metal matrix nanocomposites Table 7 Mechanical properties of ceramic nano-fillers reinforced polymer matrix nanocomposites Table 8 Mechanical properties of ceramic nano-particle reinforced metal vol.% [217] and (b) Al/SiC 3 wt.% [216] (Open Access from Metals) Melt mixing [245] Solution mixing [246] In situ polymerisation [247] In situ formation [248] Sol-Gel [249] Metal matrix nanocomposites (MMNCs)…”

“…The basic difference between these two methods is whether the reinforcements (ceramic nano-particles) are fabricated within the matrices (in-situ) [210] or separately synthesized outside by CVD [211], spray conversion process [212] or laser-induced gas-phase reaction [213] and then subsequently incorporated into metal matrices via powder metallurgy (PM) [214] or mechanical alloying (MA) [215]. Although the traditional PM method has been successfully applied to synthesis metal/ceramic nanocomposites, especially in aluminium-based matrices, it still exhibited obvious agglomerations of ceramic nano-particles and hence their inhomogeneous distribution [216,217] (Figure 20). The low wettability of as-produced ceramic nano-particles, as well as their high specific surface area, have indicated the main reasons for this drawback.…”

“…It could be improved by employing MA methods with better dispersion of ceramic nano-fillers with significant grain size reduction [218,219]. In addition, the densification of MA is mainly [216,222] although some improvements of ductility could be seen when using Mg-based matrices [223,224] without sufficient explanation. The role of ceramic nano-fillers on hindering the matrix dislocations and the effect of grain size reduction have discussed in most relevant researches that were the main reasons for hardness increments [216,222,223,[225][226][227][228].…”

A Cold-Pressing Method Combining Axial and Shear Flow of Powder Compaction to Produce High-Density Iron Parts

“…It should be noted that the obtained results can be correlated with the results obtained at the schemes of compaction with the alternative source of the process intensifiers as ultrasound, electric or magnetic pulses [43,[85][86][87][88][89][90][91][92][93]. In all of the cases, the better results can be achieved for the materials of transition metals group (Fe, Cr, Ni) that have an uncompensated spin in compounds for the formation of an adhesive bond.…”

Microstructure and Compressive Behavior of Al–Y2O3 Nanocomposites Prepared by Microwave-Assisted Mechanical Alloying

“…In the present study, the strengthening mechanism of the Al-Y 2 O 3 nanocomposites mainly depended on dispersion hardening due to the hard yttria particles present in the aluminum matrix. The increase in strength and hardness may be attributable to Orowan strengthening [44,45].…”