Elastic Moduli of Transparent Yttria

Abstract

The elastic moduli of yttria (Y 2 O 3 ) samples that were made from powders with various particle morphologies were studied by means of ultrasonic measurements. The soundwave velocities in the longitudinal and transverse modes were measured. The elastic moduli were calculated from the sound velocities and density. For the high-purity, highdensity (>5000 kg/m 3 ) Y 2 O 3 that was prepared in the present study, the average density and elastic moduli (and their standard deviations) were as follows: density () of 5020 ± 18 kg/m 3 , Young's modulus (E) of 179.8 ± 4.8 GPa, shear modulus (G) of 69.2 ± 2.0 GPa, bulk modulus (B) of 148.9 ± 3.0 GPa, and Poisson's ratio () of 0.299 ± 0.004. The average longitudinal and transverse soundwave velocities (V l and V t , respectively) were 6931 ± 65 and 3712 ± 49 m/s, respectively. The elastic moduli of lanthana-strengthened yttria (LSY) were ∼6% lower than those of high-purity Y 2 O 3 , and the value for LSY was ∼0.304. It has been argued that soundwave velocity is better than density, in regard to predicting the elastic moduli of fully dense and slightly porous materials. A linear equation that describes the change of the elastic moduli with soundwave velocity alone has been suggested. This equation was applicable to a relative elastic moduli range of 0.75-1.02.

Transmission physics and consequences for materials selection, manufacturing, and applications

“…Fine-grained microstructures with grain sizes of about 1 m were obtained from commercial and laboratory powders with particle sizes between 0.2 and 1 m by HIP at about 1350 • C. 30 After processing of powders in the range of 60-100 nm, however, a much higher HIP temperature of 1625 • C had to be applied, and the grain size increased to 50 m. 31 …”

Mechanical and elastic properties of fine-grained polycrystalline scandia and erbia as determined by indentation techniques

“…The pressed and treated compact was then hot isostatically pressed (HIPed) at 1300 • C under a pressure of 130 MPa for 5 h. 4 For Er 2 O 3 , a 99.9% pure powder (China Rare Metals Material Co. Ltd, China) was compacted and processed using a procedure identical to that used for the fabrication of transparent yttria described elsewhere. 40 Briefly the cold pressed pellets were dried and then HIPed at 1350 • C under a pressure of 150 MPa for 1.5 h.…”

“…The velocities were measured using a pulse-echo method described elsewhere. 40 The sample's density, ρ, was measured using Archimedes' method. 41 The uncertainty in the density measurements is estimated to be ≈±0.1%; that in V L ≈ ±0.1%, and that in V T ≈ ±0.1%.…”

Tungsten–vanadium–yttria alloys for fusion power reactors (II): Mechanical characterization

“…The TPB tests were performed using load spans of 16.0 and 8.5 mm for the smooth and laser-notched bars, respectively [11]. The tests were performed using displacement control with a cross-head speed of 100 μm/min and a heating rate of 30 K/min.…”