Ultrasound assisted casting of an AM60 based metal matrix nanocomposite, its properties, and recyclability

Hajo Dieringa, Lydia Katsarou, Ricardo Buzolin, Gábor Szakács, Manfred Horstmann, Martin Wolff, Chamini Mendis, Sergey Vorozhtsov, David StJohn

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Abstract

An AM60 magnesium alloy nanocomposite reinforced with 1 wt % of AlN nanoparticles was prepared using an ultrasound (US) assisted permanent-mould indirect-chill casting process. Ultrasonically generated cavitation and acoustic streaming promoted de-agglomeration of particle clusters and distributed the particles throughout the melt. Significant grain refinement due to nucleation on the AlN nanoparticles was accompanied by an exceptional improvement in properties: yield strength increased by 103%, ultimate tensile strength by 115%, and ductility by 140%. Although good grain refinement was observed, the large nucleation undercooling of 14 K limits further refinement because nucleation is prevented by the formation of a nucleation-free zone around each grain. To assess the industrial applicability and recyclability of the nanocomposite material in various casting processes, tests were performed to determine the effect of remelting on the microstructure. With each remelting, a small percentage of effective AlN nanoparticles was lost, and some grain growth was observed. However, even after the third remelting, excellent strength and ductility was retained. According to strengthening models, enhanced yield strength is mainly attributed to Hall-Petch strengthening caused by the refined grain size. A small additional contribution to strengthening is attributed to Orowan strengthening.

Original languageEnglish
Article number388
JournalMetals
Volume7
Issue number10
DOIs
Publication statusPublished - 1 Oct 2017
Externally publishedYes

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Keywords

  • AlN
  • Magnesium alloy AM60
  • Metal matrix nanocomposite (MMNC)
  • Nanoparticles
  • Strengthening mechanisms

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Dieringa, H., Katsarou, L., Buzolin, R., Szakács, G., Horstmann, M., Wolff, M., ... StJohn, D. (2017). Ultrasound assisted casting of an AM60 based metal matrix nanocomposite, its properties, and recyclability. Metals, 7(10), [388]. https://doi.org/10.3390/met7100388