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Abstract:
This review examines the concepts how cavitation bubble collapse affects crystalline structure, crystallization of newly formed structure and recrystallization. Although this subject can be discussed in a broad sense across the area of metastable crystallization, our main focus is discussing specific examples of the inorganic solids: metal, intermetallics, metal oxides and silicon. First, the temperature, up to which ultrasound heats solids is discussed. Cavitation induced changes in crystal size of intermetallic phases in binary AlNi (50 wt% of Ni) alloys allow estimating local temperatures on surfaces and in bulk material. The interplay between atomic solid state diffusion and recrystallization during bubble collapses in heterogeneous systems is revealed. Furthermore, cavitation triggered red/ox processes at solid/liquid interfaces and their influence on recrystallization are discussed for copper aluminum nanocomposites, zinc, titanium, magnesium based materials and silicon. Cavitation driven highly non-equilibrium conditions can affect thermodynamics and kinetics of mesoscopic phase formation in heterogeneous systems and in many cases boost the macroscopic performance of composite materials, notably in catalytic alloy and photocatalytic semiconductor oxide properties, corrosion resistance, biocompatibility of nanostructured surfaces, optical properties.
