Stress-enhanced dynamic grain growth during high-pressure spark plasma sintering of alumina. (1st February 2019)

• Record Type: Journal Article
• Authors: Ratzker, Barak; Wagner, Avital; Sokol, Maxim; Kalabukhov, Sergey; Frage, Nachum
• Is Part Of: Acta materialia. Volume 164(2019)
• Page Start: 390
• Page End: 399
• Publication Date: 2019-02-01
• Subjects: Alumina -- Dynamic grain growth -- High-pressure spark plasma sintering -- Strain rate; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2018.11.001
• Languages: English
• ISSNs: 1359-6454

Abstract

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. Graphical abstract: Image 1