Stress-enhanced dynamic grain growth during high-pressure spark plasma sintering of alumina

Barak Ratzker, Avital Wagner, Maxim Sokol, Sergey Kalabukhov, Nachum Frage

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

Applying high pressure during the sintering of ceramic materials is a common practice that allows for a reduction of the sintering temperature and the obtaining of fine-grained microstructures. In this work, we show that the final grain size of submicron alumina increased consistently with applied pressure during low temperature (1000–1050 °C), high pressure (500–800 MPa) spark plasma sintering. Grain size trajectories and microstructural observations indicated that stress-enhanced grain growth occurred during the final stage of the sintering process, whereas thermally controlled grain boundary migration was negligible. We suggest that this dynamic, stress-enhanced grain growth is controlled by grain-boundary sliding, grain rotation and coalescence. A strong correlation was found between calculated creep strain rates and grain growth rates, such as during superplastic deformation.

Original languageEnglish
Pages (from-to)390-399
Number of pages10
JournalActa Materialia
Volume164
DOIs
StatePublished - 1 Feb 2019

Keywords

  • Alumina
  • Dynamic grain growth
  • High-pressure spark plasma sintering
  • Strain rate

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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