Martensitic transformation in zirconiaPart I. Nanometer scale prediction and measurement of transformation induced relief

Abstract

We investigate by atomic force microscopy (AFM) the surface relief resulting from martensitic tetragonal to monoclinic phase transformation induced by low temperature autoclave aging in ceria-stabilized zirconia. AFM appears as a very powerful tool to investigate martensite relief quantitatively and with a great precision. The crystallographic phenomenological theory is used to predict the expected relief induced by the transformation, for the particular case of lattice correspondence ABC1, where tetragonal c axis becomes the monoclinic c axis. A model for variants spatial arrangement for this lattice correspondence is proposed and validated by the experimental observations. An excellent agreement is found between the quantitative calculations outputs and the experimental measurements at nanometer scale yielded by AFM. All the observed features are explained fully quantitatively by the calculations, with discrepancies between calculations and quantitative experimental measurements within the measurements and calculations precision range. In particular, the crystallographic orientation of the transformed grains is determined from the local characteristics of transformation induced relief. It is finally demonstrated that the strain energy is the controlling factor of the surface transformation induced by low temperature autoclave treatments in this material. RésuméNous avons étudié par microscopie à force atomique (MFA) les caractéristiques du relief de surface induit par la transformation martensitique quadratique-monoclinique de la zircone cériée. La transformation a été provoquée par des traitements de vieillissement en

Shape-Strain Analysis of Martensite in Ceria-Doped Zirconia

“…It is generally difficult to identify the unique c t axis of the tetragonal symmetry when the c=a ratio is close to unity, which is the case for the present specimen (c=a $ 1:018). 9,10) To overcome the difficulty, an EBSD pattern taken from a given spot was contrast enhanced via software, and the pattern was manually indexed in the tetragonal symmetry. However, there were still a few cases where a unique indexing could not be made with confidence.…”

“…For zirconia, because the cell dimensions of the two lattices are similar, the three LCs that appear possible are ABC, BCA, and CAB, which denote that a t , b t , c t of the tetragonal lattice correspond to a m , b m , c m ; b m , c m , a m ; and c m , a m , b m of the monoclinic lattice, respectively. 4,5,9) The lattice parameters of the tetragonal and monoclinic structures were adopted from the literature.…”

“…A pyramid-type martensite has only f301g t habit plane. The shape strains of the variants associated with these habit planes are effective in accommodating the shape strains of the transformation in the near-surface region, as proposed by Deville et al (2004). Although pyramidal structures appear predominantly on surfaces near the ð001Þ t plane, they also appear on surfaces near ð100Þ t and ð010Þ t planes.…”

“…10) Deville et al 9) constructed a model for the pyramidal structure based on PTMC by considering that the structure would effectively accommodate the transformation strain. According to their model, the structure consists of four martensite variants having f0:954; 0:0; 0:301g t habit planes (planar interfaces with the matrix) and a common ½0:0; 0:0; 0:164 t shear vector.…”

Osseous differentiation on freeze casted 10CeTZP-Al2O3 structures

“…Most ceramic materials are hard and brittle; however, ceria-stabilized zirconia (CeTZP) is an exception. In detail, it presents an intrinsic reinforcement mechanism, called transformation toughening, which is associated to its stress-induced martensitic transformation and notably increases its fracture toughness [5][6][7].…”