Effect of Superplastic Deformation on the Properties of Zirconia Dispersed Alumina Nanocomposite

Abstract:

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In this paper constrained extrusion of the zirconia dispersed alumina nanocomposite under superplastic conditions was conducted. The mechanical properties of deformed material were studied and its results were compared with those of the initial materials. The microstructure evolution during superplastic deformation was also analyzed. The results demonstrated that after superplastic extrusion the flexural strength, relative density, Vickers hardness as well as fracture toughness of the material increased noticeably. The flexural strength of the deformed composite even retained at a high value of 310MPa at 800°C. The fracture toughness of the material increased from 6.92 MPa·m1/2 to 8.87 MPa·m1/2 after deformation. After superplastic extrusion due to grain boundary sliding and the compressive stress state, the internal porosities in as-sintered materials were eliminated. During extrusion with grain coarsening the effect of t-ZrO2 to m-ZrO2 transformation toughening increased because more zirconia grains reached the critical dimension. Although grain coarsening may cause the decrease of the fracture toughness in some extent, the phase transformation toughening and strengthening dominated. As a result, the mechanical properties of the deformed material were improved.

Info:

Periodical:

Materials Science Forum (Volumes 551-552)

Edited by:

K.F. Zhang

Pages:

527-532

DOI:

10.4028/www.scientific.net/MSF.551-552.527

Citation:

G. Q. Chen et al., "Effect of Superplastic Deformation on the Properties of Zirconia Dispersed Alumina Nanocomposite", Materials Science Forum, Vols. 551-552, pp. 527-532, 2007

Online since:

July 2007

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Price:

$35.00

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