Composite Materials Research Progress

278
S.C. Tjong
ultrasonic waves generate nonlinear effects in molten metal such as transient cavitation and
acoustic streaming. Acoustic cavitation involves the formation, growth, pulsating and
collapsing of tiny bubbles, thereby yielding transient local hot spots and implosive impacts to
break up the clustered particles. The strong impact and local high temperatures enhance the
wettability between molten metal and nanoparticles. Consequently, cast Al-based
nanocomposite with better dispersion of ceramic nanoparticles can be prepared (Fig. 4).
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Figure 2. Continued on next page.