Microstructure and microhardness of SiC nanoparticles reinforced magnesium composites fabricated by ultrasonic method

Strong, Ductile Magnesium-Zinc Nanocomposites

“…In prior studies with aluminum alloys and AZ91D matrices, nanoparticle composites merely maintain the original ductility. [11,12,28] Thus, the ductility enhancement seen in Table I and Figure 1 is quite remarkable.…”

“…Current solidification processing methods for MMNCs are limited in size and geometric complexity, preventing designers from achieving the design flexibility desired for complex structures (e.g., engine blocks). Recently, Lan et al [11] and Yang et al [12,13] developed a new technique that combined solidification processing (e.g., casting) with an ultrasonic cavitation based dispersion of nanoparticles in metal melts. Nanoparticle reinforced magnesium and aluminum alloys were successfully fabricated.…”

“…Experimental results show a nearly uniform distribution and good dispersion of the SiC nanoparticles within the metal matrix, resulting in significantly improved mechanical strength while maintaining useful ductility. [11][12][13] It was reported [14] that ultrasonic cavitation can produce transient (in the order of nanoseconds) micro ''hot spots'' that can have temperatures of about 5000°C, pressures above 100 MPa, and heating and cooling rates above 10 10°C /s. The locally extreme conditions induced by the ultrasound can effectively disperse nanoparticles into molten metals due to the strong impact during cavitation and enhanced nanoparticle wettability.…”

Corrosion behaviour of Al/SiC and Al/Al2O3 nanocomposites

“…The SiC and Al 2 O 3 nanoparticulates distribution in the Al matrix was fairly uniform. Although small agglomerates in Al/SiC and Al/Al 2 O 3 nanocomposites still existed in the matrix, the agglomerates have been greatly improved when compared with the severe agglomerates in nanocomposites fabricated using traditional mechanical stirring method 9 . Figure 5 shows the variation of the corrosion rate of Al/Al 2 O 3 and Al/SiC nanocomposites with the exposure time in 1 M HCl at ambient temperature.…”

Synthesis and Characterization of TiAl‐Based Nanocomposites by a Melt Electromagnetic Stirring Process

“…[4] Liquid-state processing methods have the advantage of near-net shape in the following casting process, but large-scale agglomerates have been thought very hard to be dispersed well due to the material's high surface energy and poor wettability in the liquid state, especially in non-reactive systems. [9] However, there have been successful cases in which fine dispersions of nanoparticles were obtained, such as by enhancing the force field through ultrasonic dispersion (USD), [10,11] improving the wetting between the particles and the melt through adding active agents and combing with mechanical stir mixing. [12] Both methods have been verified feasible in aluminum alloys, but fabrication of g-TiAl-based nanocomposites using these methods seems to be a double-edged sword because, on one hand, the highly active TiAl melt may improve the wettability of nanoparticles without the addition of other active agents but, on the other hand, contamination from the USD probe or the mechanical blade can hardly be avoided.…”