Premium
Nucleation and Growth Characteristics of Cavities during the Early Stages of Tensile Creep Deformation in a Superplastic Zirconia–20 wt% Alumina Composite
Author(s) -
Owen David M.,
Chokshi Atul H.,
Nutt Steven R.
Publication year - 1997
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1997.tb03139.x
Subject(s) - superplasticity , materials science , creep , nucleation , deformation (meteorology) , composite material , ultimate tensile strength , grain size , ductility (earth science) , grain boundary sliding , grain boundary , cubic zirconia , composite number , ceramic , stress (linguistics) , grain growth , metallurgy , microstructure , thermodynamics , linguistics , philosophy , physics
Constant‐stress tensile creep experiments on a superplastic 3‐mol%‐yttria‐stabilized tetragonal zirconia composite with 20 wt% alumina revealed that cavities nucleate relatively early during tensile deformation. The number of cavities nucleated increases with increasing imposed stress. The cavities nucleate at triple points associated largely with an alumina grain, and then grow rapidly in a cracklike manner to attain dimensions on the order of the grain facet size. It is suggested that coarser‐grained superplastic ceramics exhibit lower ductility due to the ease in formation of such grain boundary facet‐cracks and their interlinkage to form a macroscopic crack of critical dimensions.