Phase transitions Vol. 78, Nos. 7-8, September 2005, 539-545 Taylor franci Crystallography of the tetragonal-to-monoclinic phase transformation in ceria-zirconia N. NAVRUZ Faculty of Science, Department of Physics, Ankara University, Tandogan 06100 Ankara, Turkey (Received 18 August 2004: in final form 25 April 2005) a detailed understanding of the transformation toughening process in zirconia- containing ceramics requires the application of the crystallographic theory of martensitic transformation. Therefore, the crystallographic analysis of the tetragonal-to-monoclinic transformation in ceria-zirconia was performed by using both the infinitesimal deformation approach and Wechsler-Lieberman- Read phenomenological crystallographic theory. All crystallographic parameters such as the habit plane orientation, orientation relationship between the parent and product phases, the direction of the total shape deformation, the amount of the lattice invariant strain. etc. were calculated. The results obtained from the infinitesimal deformation approach were in agreement with those calculated from phenomenological crystallographic theory and also with experimental Keywords: Martensitic transformation; Crystallographic theory; Zirconia-based ceramics PACS numbers: 81. 30Kf: 61.50Ks 1. Introduction Martensitic transformation from the tetragonal(o) to monoclinic (m) phase in the zirconia system has been the subject of great interest in recent years [1-3]. The t-m transformation occurring in the ceria-stabilized polycrystalline tetragonal zirconia is martensitic in nature[4-9]. The transformation may be either stress-induced, or may occur thermally on cooling to below the Ms temperature. The t-> m transforma tion is technologically important because it is the source of both transformation toughening and significant transformation plasticity [10, 11] in ceria-zirconia and other zirconia-containing ceramics In the case of the t to m transformation in partially stabilized zirconia there are three possible, simple correspondences that depend on which monoclinic axis is derived from the unique c, axis of the tetragonal parent phase. The tetragonal ct axis can become the am, bm or cm axis of the monoclinic phase, hence the three Fax:+90312 223 2395. Tel:+903122126720 Email: navruz@science. ankara. edu. tr Phase Transitions IsSN 0141-1594 print/ISSN 1029-0338 online o 2005 Taylor Francis http://www.tandf.co.uk/journals DOl:10.108001411590500158770Phase Transitions, Vol. 78, Nos. 7–8, September 2005, 539–545 Crystallography of the tetragonal-to-monoclinic phase transformation in ceria-zirconia N. NAVRUZ* Faculty of Science, Department of Physics, Ankara University, Tandogan, 06100 Ankara, Turkey (Received 18 August 2004; in final form 25 April 2005) A detailed understanding of the transformation toughening process in zirconia￾containing ceramics requires the application of the crystallographic theory of martensitic transformation. Therefore, the crystallographic analysis of the tetragonal-to-monoclinic transformation in ceria-zirconia was performed by using both the infinitesimal deformation approach and Wechsler–Lieberman– Read phenomenological crystallographic theory. All crystallographic parameters such as the habit plane orientation, orientation relationship between the parent and product phases, the direction of the total shape deformation, the amount of the lattice invariant strain, etc. were calculated. The results obtained from the infinitesimal deformation approach were in agreement with those calculated from phenomenological crystallographic theory and also with experimental observations. Keywords: Martensitic transformation; Crystallographic theory; Zirconia-based ceramics PACS numbers: 81.30 Kf; 61.50 Ks 1. Introduction Martensitic transformation from the tetragonal (t) to monoclinic (m) phase in the zirconia system has been the subject of great interest in recent years [1–3]. The t!m transformation occurring in the ceria-stabilized polycrystalline tetragonal zirconia is martensitic in nature [4–9]. The transformation may be either stress-induced, or may occur athermally on cooling to below the Ms temperature. The t ! m transforma￾tion is technologically important because it is the source of both transformation toughening and significant transformation plasticity [10, 11] in ceria-zirconia and other zirconia-containing ceramics. In the case of the t to m transformation in partially stabilized zirconia there are three possible, simple correspondences that depend on which monoclinic axis is derived from the unique ct axis of the tetragonal parent phase. The tetragonal ct axis can become the am, bm or cm axis of the monoclinic phase, hence the three *Fax: þ90 312 223 2395. Tel.: þ90 312 212 6720. Email: navruz@science.ankara.edu.tr Phase Transitions ISSN 0141-1594 print/ISSN 1029-0338 online # 2005 Taylor & Francis http://www.tandf.co.uk/journals DOI: 10.1080/01411590500158770