Effect of grain size on superplastic behavior of Y-TZP

Journal Article · Sun Apr 01 04:00:00 EDT 1990 · Scripta Metallurgica; (United States)

DOI:https://doi.org/10.1016/0956-716X(90)90238-C· OSTI ID:5736965

Nieh, T G; Wadsworth, J ^[1]

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1. Lockheed Missiles and Space Co. Inc., Research and Development Div., O/9310, B/204, Palo Alto, CA (US)

This paper reports that grain size strongly influences the properties of fine-grained superplastic metal alloys. In principle, fine grain sizes enhance grain boundary sliding which is the dominant superplastic deformation mechanism. Recently, some fine-grained ceramics have been shown to be superplastic in tension. A maximum tensile elongation of about 800% has been recorded in a yttria-stabilized tetragonal zirconia polycrystal (Y-TZP). During superplastic deformation, concurrent grain growth, and in particular dynamic grain growth, was observed in this material. It has been demonstrated that this concurrent grain growth strongly affects the superplastic flow stress in the material, and also confuses the accurate determination of the stress dependency of the superplastic strain rate. It is important, therefore, to understand the precise grain size dependence of superplastic flow in ceramics. It has been shown that the superplastic strain rate of Y-TZP is inversely proportional to the grain size raised to a 1.8 power. The effect of concurrent grain growth, however, was not considered in their analyses.

• OSTI ID: 5736965
• Journal Information: Scripta Metallurgica; (United States), Journal Name: Scripta Metallurgica; (United States) Vol. 24:4; ISSN 0036-9748; ISSN SCRMB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360203 -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ALLOYS
CHALCOGENIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
DEFORMATION
GRAIN BOUNDARIES
GRAIN SIZE
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
POLYCRYSTALS
SIZE
TENSILE PROPERTIES
TETRAGONAL LATTICES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM ADDITIONS
YTTRIUM ALLOYS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES