Final stage free sintering and sinter forging behavior of a yttria-stabilized tetragonal zirconia

Owen, DM and Chokshi, AH (1998) Final stage free sintering and sinter forging behavior of a yttria-stabilized tetragonal zirconia. In: Acta Materialia, 46 (02). pp. 719-729.

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Abstract

A comprehensive study was undertaken to characterize quantitatively the final stage sintering behavior of a yttria-stabilized tetragonal zirconia (YTZ) under free sintering and sinter forging conditions and to evaluate the role of deformation which occurs concurrently during sinter forging. The results indicated that the activation energies for densification were 585 +/- 45 and 620 +/- 70 kJ mol(-1) during free sintering and sinter forging, respectively, which were similar to the value of 650 +/- 70 kJ mol(-1) observed for deformation during sinter forging. Sinter forging experiments revealed that the densification rate, (rho) over dot, was proportional to sigma(2), where sigma is the applied stress, whereas the deformation rate, (epsilon) over dot, was proportional to sigma(3). Microstructural observations showed that grain growth kinetics were independent of the volume fraction of porosity. After extensive creep deformation during sinter forging, grains remained equiaxed with average linear intercept grain sizes of similar to 180 nm. A detailed analysis of possible mechanisms revealed that densification in YTZ is controlled by the rate of grain boundary vacancy absorption. Furthermore, it was demonstrated that deformation mechanisms in porous and dense YTZ are identical.

Item Type:	Journal Article
Publication:	Acta Materialia
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	21 Jul 2009 10:56
Last Modified:	19 Sep 2010 05:24
URI:	http://eprints.iisc.ac.in/id/eprint/18652

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