Processing of Magnesium-Based Metal Matrix Nanocomposites by Ultrasound-Assisted Particle Dispersion: A Review

Abstract

Magnesium-based metal matrix nanocomposites (MMNCs) are an important topic in the development of lightweight structural materials, because their optimized properties are of great interest to the automotive and aerospace industries. Moreover, components with functional properties will also be manufactured from Mg-MMNCs in the future. With a large surface to volume ratio, nanoparticles in the magnesium matrix have an immense effect on mechanical properties, even at low concentrations. The mechanical properties of these materials can be tailored using ceramic nanoparticles, which have been available at a very low cost for a number of years. However, the particle concentration, chemical composition, particle size, and process parameters must be attuned to the respective alloy, in order to influence the resulting properties. When using very small particles, a major problem is to homogeneously distribute the particles in the melt. Due to their large surface area, strong van der Waals forces act to hold the particles together in clusters. At the same time, wettability of the particles with a magnesium melt is very poor. Ultrasonic stirring processes have proven their effectiveness in the de-agglomeration and dispersion of nanoparticles. This review presents ultrasound-assisted processes for the production of these materials and describes some properties of the resulting Mg-MMNCs.

In Situ Tomographic Observation of Dendritic Growth in Mg/Al Matrix Composites

“…Interestingly, the addition of both NP and MPs to the melt seems to reduce the amount of porosity formed. This could be due to several reasons: 1. the ultrasonic treatment used to process the Al2O3 containing melts included a degassing operation [20]; 2. the refinement of the microstructure also refines and reduces porosity [21]. Overall, however, it appears that the effect of Al2O3 particles, either micron or nano-sized on the solidification structure of Al-10Cu was less significant in refining the grain structure as compared to that of the SiC NPs in the Mg-25Zn-7Al.…”

Synthesis of Magnesium Based Nano-composites

“…This causes inferior mechanical properties of the end composites. Ultrasonic (UST) cavitation method is a relatively more effective technique to disperse the reinforcement into the matrix material in MMCs [17]. By introducing the ultrasonic waves with power and frequency range of as low as 1.5-4.0 kW and 17.5-20 kHz the agglomerates can be fragmented, and a uniform distribution of reinforcement can be realized in the liquid melt.…”

“…By introducing the ultrasonic waves with power and frequency range of as low as 1.5-4.0 kW and 17.5-20 kHz the agglomerates can be fragmented, and a uniform distribution of reinforcement can be realized in the liquid melt. This method has been adopted so far to produce MMNCs reinforcing with CNTs, AlN, SiC, B 4 C and Al 2 O 3 [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. The schematic of UST setup is shown in the Figure 2.…”

Advanced Metal Matrix Nanocomposites

“…This processing is followed by appropriate solidification, e.g., a sufficiently slow cooling rate [21], which can give rise to homogeneous microstructure in the nanocomposite. Thus, the optimum enhancement effect of nanoparticles on the mechanical properties of nanocomposite can be achieved [115].…”