Elastic properties of single-crystalline and consolidated nano-structured yttrium oxide at room temperature

Abstract

High resolution Brillouin spectroscopy was used to characterize the elastic stiffness properties of consolidated nano-crystalline yttrium oxide as well as of the related single-crystalline state. Defect enriched grain boundaries are discussed as sources for the extremely soft elastic properties of the nano-crystalline state.

Effect of Initial Particle and Agglomerate Size on the Elastic Moduli of Porous Yttria (Y2O3)

“…Table III gives the values of the measured ρ, E , and G , and evaluated E 0 , G 0 , and ν 0 data points of polycrystalline samples of high purity high‐density (typically ), 28–31,33 and the values of the Voigt–Reuss–Hill approximation 16,30,31 for the elastic moduli of polycrystalline material from the elastic constants of single crystals.…”

“… Residual stress and plastic deformation can affect the elastic moduli 42 . Baller et al 30 indicated that solidification of single crystal yttria and its phase transition during cooling, might result in internal stresses. The presence of microcracks affects both the measured elastic constants of single crystal and the elastic moduli of polycrystalline matter. Compositional stoichiometry affects the elastic moduli of some oxide ceramics, 43 and affects some of the physical properties of the α‐Y 2 O 3− X . 44 The presence of large grains might reduce the elastic moduli of metals 41 …”

“…For nc‐Y 2 O 3 (17 nm) Baller et al 30 reported that the longitudinal modulus C 11 =ρ V L 2 , is about 25% of that of micrometric yttria. This is consistent with recent article indicating that in nc‐MgO the elastic moduli are lower than those of micrometric size MgO 58 .…”

“…[19][20][21][22] Hence for porous ceramics in general and for yttria (Y 2 O 3 ) in particular, a span of the elastic moduli results exists for vast porosity range. 6,9,22 Such a variation in the elastic moduli of Y 2 O 3 is demonstrated when the data points and experimental predicting models given in the literature [23][24][25][26][27][28][29][30][31][32][33] are plotted against r à (Fig. 1).…”

“… The dependence of the Young's modulus on the normalized density of Y 2 O 3 , from literature results 23–33 . In addition, we overlaid various approximations of the change of the Young's modulus with porosity.…”