scholarly journals Evaluation of Phase Transformation and Mechanical Properties of Metastable Yttria-Stabilized Zirconia by Nanoindentation

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1677 ◽  
Author(s):  
Ningning Song ◽  
Ziyuan Wang ◽  
Yan Xing ◽  
Mengfei Zhang ◽  
Peng Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Young’S Modulus ◽  
Tetragonal Phase ◽  
Young's Modulus ◽  
Traditional Approach ◽  
Yttria Stabilized Zirconia ◽  
Phase Identification ◽  
Stabilized Zirconia ◽  
T Phase

Microscopical nonuniformity of mechanical properties caused by phase transformation is one of the main reasons for the failure of the materials in engineering applications. Accurate measurement of the mechanical properties of each phase is of virtual importance, in which the traditional approach like Vickers hardness cannot accomplish, due to the large testing range. In this study, nanoindentation is firstly used to analyze the mechanical properties of each phase and demonstrate the phase transformation in thermal barrier coatings during high-temperature aging. The distribution of T-prime metastable tetragonal phase, cubic and tetragonal phase is determined by mapping mode of nanoindentation and confirmed with X-ray diffraction and scanning electron microscope observation. The results show that during 1300 °C aging, the phase transition of metastable Yttria-Stabilized Zirconia induces the quick decrease of T′ phase content and an increase of T and C phases accordingly. It is found that there are some fluctuations in the mechanical properties of individual phase during annealing. The hardness and Young’s modulus of T′ increase at first 9 h, due to the precipitation of Y3+ lean T phase and then decrease to a constant value accompanied by the precipitation of Y3+ rich C phase. The relevant property of C phases also increases a little firstly and then decreases to a constant, due to the homogenization of Y3+ content, while the hardness and Young’s modulus of T phase remain unchanged. After aging of 24h the hardness of T′, C and T phases are 20.5 GPa, 21.3 GPa and 19.1 GPa, respectively. The Young’s modulus of T′, C and T phases are 274 GPa, 275 GPa and 265 GPa, respectively. Present work reveals the availability of nanoindentation method to demonstrate the phase transformation and measure mechanical properties of composites. It also provides an efficient application for single phase identification of ceramics.

Evaluation of Mechanical Properties of SOFC Components by Nano-Indentation Tests

2010 ◽  
Author(s):  
Hideaki Ito ◽  
Kazuhisa Sato ◽  
Atsushi Unemoto ◽  
Koji Amezawa ◽  
Tatsuya Kawada
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Crystal Orientation ◽  
Young's Modulus ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Indentation Method ◽  
Nano Indentation ◽  
Electron Backscattering Diffraction ◽  
Indentation Tests

The Young’s modulus and the hardness of single crystals and polycrystalline sintered compacts of yttria-stabilized zirconia (YSZ), (Y2O3)x(ZrO2)1−x (x = 0.08, 0.10) was investigated by using the nano-indentation method. Together with results obtained by the secondary electron microscope observation and the electron backscattering diffraction analysis, the effect of the crystal orientation on the mechanical properties was discussed. It was empirically demonstrated that the Young’s modulus of YSZ depends on the crystal orientation. The Young’s modulus of YSZ showed the highest value on the (001) surface while the lowest value on the (111) surface. However, the observed anisotropy of the Young’s modulus was rather small compared with predicted one from the single crystal elastic constants in literature. Compared with the Young’s modulus, the anisotropy of the hardness of YSZ was less significant.

The Effects of Silica Content and Thermal Cycles on Young’s Modulus and Residual Stresses in Yttria Stabilized Zirconia Thermal Barrier Coatings

1997 ◽  
Author(s):  
R.T.R. McGrann ◽  
E.F. Rybicki ◽  
J.R. Shadley ◽  
R.E. Sanchez ◽  
W.J. Brindley
Keyword(s):  
Residual Stresses ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Silica Content ◽  
Yttria Stabilized Zirconia ◽  
Ceramic Layer ◽  
Thermal Barrier ◽  
Stabilized Zirconia ◽  
Thermal Cycles ◽  
Plasma Sprayed

Abstract The Young's modulus of the ceramic top coat of a plasma sprayed thermal barrier coating (TBC) has been reported to vary by as much as a factor of three with changes in processing parameters and by as much as a factor of four due to prolonged thermal exposure. Since the residual stress is expected to vary directly with the modulus of the ceramic layer, it follows that a change in modulus will change the residual stresses in the ceramic layer. The objective of this study was to evaluate the modulus of plasma sprayed coatings as a function of thermal cycle exposure and silica content of the ceramic. The study employed the Cantilever Beam Bending Method to examine Young's modulus for an yttria stabilized zirconia TBC applied by plasma spraying, for zero and ten thermal cycles and for silica contents of 0.1% and 1.0%. Results are discussed in terms of mechanisms that may affect modulus and the effect of modulus variations on residual stresses.

scholarly journals The Ultrafine-Grain Yttria-Stabilized Zirconia Reinforced β-Titanium Matrix Composites

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 240
Author(s):  
Daria Piechowiak ◽  
Andrzej Miklaszewski ◽  
Natalia Makuch-Dziarska
Keyword(s):  
Corrosion Resistance ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Young Modulus ◽  
Yttria Stabilized Zirconia ◽  
Ultrafine Grain ◽  
Titanium Matrix ◽  
Stabilized Zirconia ◽  
Fine Grain ◽  
Beta Titanium

Ti(β) alloys have become an important class in the biomedical field due to low Young’s modulus, excellent physical properties, and biocompatibility. However, their properties, like biocompatibility and, also, low wear resistance, can be still enhanced. To improve those properties, a composites approach can be applied. This research shows a new approach of the composite structure fabrication by powder metallurgy methods which for a stabile yttria-stabilized zirconia (YSZ) reinforcement phase could be obtained in the ultra-fine grain range beta-titanium matrix. In this work, the composites based on ultrafine-grain Ti-xMo (x = 23 wt%, 27 wt%, 35 wt%) alloys with addition 3 wt%, 5 wt% or 10 wt% YSZ, and 1 wt% Y2O3 were fabricated by the mechanical alloying and hot-pressing approach. Obtained composites were characterized in terms of their phase composition, microstructure, Young’s modulus, hardness, surface free energy (SFE), and corrosion resistance. The structure of composites consists of phases based on Ti–Mo, Ti(α), and YSZ. The oxide (YSZ) powder tends to agglomerate during processing, which is revealed in composites based on Ti23Mo and Ti27Mo. However, composites based on Ti35Mo are characterized by a high degree of dispersibility and this influences significantly the hardness value of the composites obtained. Only in the case of composites based on Ti35Mo, the decrease in Young’ Modulus is observed. All composites possess a hydrophilic surface property and good corrosion resistance.

Microstructural examination of modified yttria stabilized zirconia by EM analytical techniques

1986 ◽  
Vol 44 ◽  
pp. 842-843
Author(s):  
W. W. Davison ◽  
R. C. Buchanan
Keyword(s):  
Mechanical Properties ◽  
Analytical Techniques ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Transmission Microscopy ◽  
Sintering Aid ◽  
Densification Temperature ◽  
Chemical Inertness ◽  
Scanning Transmission ◽  
Microstructural Examination

Yttria stabilized zirconia (YSZ) has become a significant technological material due to its high ionic conductivity, chemical inertness, and good mechanical properties. Temperatures on the order of 1700°C are required, however, to densify YSZ to the degree necessary for good electrical and mechanical properties. A technique for lowering the densification temperature is the addition of small amounts of material which facilitate the formation of a liquid phase at comparatively low temperatures. In this study, sintered microstructures obtained from the use of Al2O3 as a sintering aid were examined with scanning, transmission, and scanning transmission microscopy (SEM, TEM, and STEM).

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

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