Physica B 350 (2004) e1019–e1022 SANS investigations of pore anisotropy in superplastically deformed ceramics Vasyl Ryukhtin a,b, *, Jan $ Saroun a , Stefanus Harjo c , Yoshinobu Motohashi c , Albrecht Wiedenmann d , Pavel Strunz a,e a Nuclear Physics Institute, 25068 $ Rem near Prague, Czech Republic b Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Praha 2, Czech Republic c Ibaraki University, Faculty of Engineering, Research Center for Superplasticity, Hitachi, Ibaraki 316-8511, Japan d Hahn-Meitner-Institut (HMI), Glienicker Str. 100, 14109 Berlin, Germany e Paul Scherrer Institute, 5232 Villigen PSI, Switzerland Abstract Superplastically deformed samples of 3 mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) and 3Y- TZP with 20 wt% of Al 2 O 3 were studied by SANS with the aim to compare cavitation behaviours under different deformation conditions. Though the average size of cavities formed during deformation is so large that they can be measured only by high-resolution SANS techniques, conventional SANS method permitted us to measure their specific surface and aspect ratio quite effectively. Analysis of the two-dimentional SANS data clearly showed two qualitatively different cavitation regimes corresponding to the low-stress (low-strain rate and high-temperature) and high-stress conditions, respectively. In the latter case, a new type of flat pores transversal to the tension axis was observed, in addition to the usually present slightly prolate cavities. r 2004 Elsevier B.V. All rights reserved. PACS: 68.55; 61.45 Keywords: Small-angle neutron scattering; Tetragonal zirconia polycrystals; Superplastic ceramics; Cavitation 1. Introduction Evolution of cavities during superplastic defor- mations of ceramics is closely related to the physical mechanisms, which can control the deformation process [1]. Measurements of these cavities (e.g. size distribution, volume fraction, etc.), therefore, help to understand these mechan- isms and consequently to find the deformation conditions (temperature, strain rate), grain size or material composition, which should be optimal for plastic working. Small-angle neutron scattering (SANS) method is particularly a suitable method for this purpose and has been used in our earlier work [2] to study cavitation behaviour in 3 mol% ARTICLE IN PRESS *Corresponding author. Nuclear Physics Institute, $ Rem near Prague 25068, Czech Republic. Tel.: +420-266-173-140; fax: +420-220-940-141. E-mail address: ryukhtin@ujf.cas.cz (V. Ryukhtin). 0921-4526/$ - see front matter r 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.physb.2004.03.280