Mechanical Properties of Cubic (U,Zr)O2

2018 ◽  
Vol 4 (3) ◽  
Author(s):  
Toru Kitagaki ◽  
Takanori Hoshino ◽  
Kimihiko Yano ◽  
Nobuo Okamura ◽  
Hiroshi Ohara ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Nuclear Power ◽  
Ultrasonic Pulse ◽  
Zro2 Content ◽  
Debris Removal ◽  
Working Principle ◽  
Water Reactors ◽  
Pulse Echo

Evaluation of fuel debris properties in the Fukushima Daiichi nuclear power plant (1F) is required to develop fuel debris removal tools. In the removal of debris resulting from the Three Mile Island unit 2 (TMI-2) accident, a core-boring system played an important role. Considering the working principle of core boring, hardness, elastic modulus, and fracture toughness were found to be important fuel debris properties that profoundly influenced the performance of the boring machine. It is speculated that uranium and zirconium oxide solid solution (U,Zr)O2 is one of the major materials in the fuel debris from 1F. In addition, the Zr content of the fuel debris from 1F is expected to be higher than that of the debris from TMI-2 because the 1F reactors were boiling-water reactors. In this research, the mechanical properties of cubic (U,Zr)O2 samples containing 10%–65% ZrO2 are evaluated. The hardness, elastic modulus, and fracture toughness are measured by the Vickers test, ultrasonic pulse echo method, and indentation fracture method, respectively. In the case of (U,Zr)O2 samples containing less than 50% ZrO2, Vickers hardness and fracture toughness increased, and the elastic modulus decreased slightly with increasing ZrO2 content. Moreover, all of those values of the (U,Zr)O2 samples containing 65% ZrO2 increased slightly compared to (U,Zr)O2 samples containing 55% ZrO2. ZrO2 content affects fracture toughness significantly in the case of samples containing less than 10% ZrO2. Higher Zr content (exceeding 50%) has little effect on the mechanical properties.

Fabrication of Carbon Nanotube Reinforced Boron Carbide Composite by Hot-Pressing Following Extrusion Molding

2014 ◽  
Vol 616 ◽  
pp. 27-31 ◽  
Author(s):  
Tomohiro Kobayashi ◽  
Katsumi Yoshida ◽  
Toyohiko Yano
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Carbon Nanotube ◽  
Boron Carbide ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Extrusion Direction ◽  
Sem Observation

The CNT/B4C composite with Al2O3 additive was fabricated by hot-pressing following extrusion molding of a CNT/B4C paste, and mechanical properties of the obtained composite were investigated. Many CNTs in the composite aligned along the extrusion direction from SEM observation. 3-points bending strength of the composite was slightly lower than that of the monolithic B4C. Elastic modulus and Vickers hardness of the composite drastically decreased with CNT addition. Fracture toughness of the composite was higher than that of the monolithic B4C.

Fracture Toughness and Adhesion Energy of Sol-gel Coatings on Glass

2002 ◽  
Vol 17 (1) ◽  
pp. 224-233 ◽  
Author(s):  
Jaap Den Toonder ◽  
Jürgen Malzbender ◽  
Gijsbertus De With ◽  
Ruud Balkenende
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Sol Gel ◽  
Industrial Applications ◽  
Adhesion Energy ◽  
Scratch Testing ◽  
New Methods ◽  
Quantitative Results ◽  
Coating Fracture

The reliability of coatings that are used in industrial applications critically depends on their mechanical properties. Nanoindentation and scratch testing are well-established techniques to measure some of these properties, namely the elastic modulus and hardness of coatings. In this paper, we investigate the possibility of also assessing the coating fracture toughness and the energy of adhesion between the coating and the substrate using indentation and scratch testing. Various existing and new methods are discussed, and they are illustrated by measurements on particle-filled sol-gel coatings on glass. All methods are based on the occurrence of cracking, and they are therefore only applicable to coating systems that act like brittle materials and exhibit cracking during indentation and scratching. The methods for determining the fracture toughness give comparable results, but the values still differ to within about 50%. The values of the adhesion energy obtained from different measurements are consistent, but it remains uncertain to which extent the obtained values are quantitatively correct. The results show that the methods used are promising, but more research is needed to obtain reliable quantitative results.

A Method to Determine Fracture Toughness Using Berkovich Indenter for Bulk Materials

2013 ◽  
Vol 331 ◽  
pp. 456-460
Author(s):  
Min He ◽  
Duan Hu Shi ◽  
Feng Yang ◽  
Ning Zhang ◽  
Hua Feng Guo
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Penetration Depth ◽  
Effective Elastic Modulus ◽  
Berkovich Indenter ◽  
Bulk Materials ◽  
Ductile Materials ◽  
Penetration Depths ◽  
Determine Fracture Toughness

An indentation approach with Berkovich indenter is proposed to determine fracture toughness for ductile materials. With decrease of effective elastic modulus, an approximate linear relationship between logarithmic plastic penetration depth and logarithmic effective elastic modulus, and a quadratic polynomial relationship between the plastic penetration depths and penetration loads are exhibited by indentation investigation with Berkovich indenter. The damage constructive equation of effective elastic modulus is proposed to determine the critical effective elastic modulus at the fracture point, which is the key problem to calculate the indentation energy to fracture. The critical plastic penetration depth is identified after the critical effective elastic modulus can be predicted by conventional mechanical properties. The fracture toughness is calculated according to the equation of penetration load, plastic penetration depth and the critical plastic penetration depth.

scholarly journals Mechanical Properties of 3C-SiC Films for MEMS Applications

2007 ◽  
Vol 1049 ◽  
Author(s):  
Jayadeep Deva Reddy ◽  
Alex A. Volinsky ◽  
Christopher L. Frewin ◽  
Chris Locke ◽  
Stephen E. Saddow
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Plastic Deformation ◽  
Elastic Modulus ◽  
Single Crystal ◽  
Elastic Contact ◽  
Si Substrates ◽  
Sic Films

AbstractThere is a technological need for hard thin films with high elastic modulus and fracture toughness. Silicon carbide (SiC) fulfills such requirements for a variety of applications at high temperatures and for high-wear MEMS. A detailed study of the mechanical properties of single crystal and polycrystalline 3C-SiC films grown on Si substrates was performed by means of nanoindentation using a Berkovich diamond tip. The thickness of both the single and polycrystalline SiC films was around 1-2 μm. Under indentation loads below 500 μN both films exhibit Hertzian elastic contact without plastic deformation. The polycrystalline SiC films have an elastic modulus of 457 GPa and hardness of 33.5 GPa, while the single crystalline SiC films elastic modulus and hardness were measured to be 433 GPa and 31.2 GPa, respectively. These results indicate that polycrystalline SiC thin films are more attractive for MEMS applications when compared with the single crystal 3C-SiC, which is promising since growing single crystal 3C-SiC films is more challenging.

Effect of Preheating and Fatiguing on Mechanical Properties of Bulk-fill and Conventional Composite Resin

2019 ◽  
Vol 45 (4) ◽  
pp. 387-395
Author(s):  
AA Abdulmajeed ◽  
TE Donovan ◽  
R Cook ◽  
TA Sulaiman
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Composite Resin ◽  
Statistical Significance ◽  
Composite Resins ◽  
Significant Difference ◽  
Diametral Tensile Strength

Clinical Relevance Bulk-fill composite resins may have comparable mechanical properties to conventional composite resin. Preheating does not reduce the mechanical properties of composite resins. SUMMARY Statement of Problem: Bulk-fill composite resins are increasingly used for direct restorations. Preheating high-viscosity versions of these composites has been advocated to increase flowability and adaptability. It is not known what changes preheating may cause on the mechanical properties of these composite resins. Moreover, the mechanical properties of these composites after mastication simulation is lacking. Purpose: The purpose of this study was to evaluate the effect of fatiguing and preheating on the mechanical properties of bulk-fill composite resin in comparison to its conventional counterpart. Methods and Materials: One hundred eighty specimens of Filtek One Bulk Fill Restorative (FOBR; Bulk-Fill, 3M ESPE) and Filtek Supreme Ultra (FSU; Conventional, 3M ESPE) were prepared for each of the following tests: fracture toughness (International Organization for Standardization, ISO 6872), diametral tensile strength (No. 27 of ANSI/ADA), flexural strength, and elastic modulus (ISO Standard 4049). Specimens in the preheated group were heated to 68°C for 10 minutes and in the fatiguing group were cyclically loaded and thermocycled for 600,000 cycles and then tested. Two-/one-way analysis of variance followed by Tukey Honest Significant Difference (HSD) post hoc test was used to analyze data for statistical significance (α=0.05). Results: Preheating and fatiguing had a significant effect on the properties of both FSU and FOBR. Fracture toughness increased for FOBR specimens when preheated and decreased when fatigued (p=0.016). FOBR had higher fracture toughness value than FSU. Diametral tensile strength decreased significantly after fatiguing for FSU (p=0.0001). FOBR had a lower diametral tensile strength baseline value compared with FSU (p=0.004). Fatiguing significantly reduced the flexural strength of both FSU and FOBR (p=0.011). Preheating had no effect on the flexural strength of either FSU or FOBR. Preheating and fatiguing significantly decreased the elastic modulus of both composite resins equally (p>0.05). Conclusions: Preheating and fatiguing influenced the mechanical properties of composite resins. Both composites displayed similar mechanical properties. Preheating did not yield a major negative effect on their mechanical properties; the clinical implications are yet to be determined.

Mechanical properties and residual stress of HVOF sprayed nanostructured WC-17Co coatings

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040041
Author(s):  
Hairong Sun ◽  
Jinpeng Yu ◽  
Guoqing Gou ◽  
Wei Gao
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Residual Stress ◽  
Elastic Modulus ◽  
Tensile Stress ◽  
Compressive Residual Stress ◽  
Hvof Spray ◽  
Spray Technique ◽  
Oxygen Flame ◽  
Conventional Coating

Nanostructured WC-17Co, 2C-12Co coatings and conventional WC-17Co coating were prepared by High Velocity Oxygen Flame (HVOF) spray technique. The elastic modulus, fracture toughness and crack spread path were studied. The residual stress, different phases, microstructure from surface to the depth of coatings were also analyzed. While the nanostructured WC-12Co coating showed the highest elastic modulus, the nanostructured WC-17Co coating has the highest fracture toughness. The compressive residual stress of the nanostructured coatings was higher than the conventional coating. Both WC and W2C phases showed compressive residual stress, but Co6W6C phase showed tensile stress. The distribution of residual stress showed that the stress is the lowest at the surface and the highest close to the interface.

Microstructure and Mechanical Properties of Al2O3/ZrO2 Composites Prepared by Gelcasting

2007 ◽  
Vol 280-283 ◽  
pp. 1057-1060
Author(s):  
Bao Xiang Jiao ◽  
Tai Qiu ◽  
Chun Cheng Li ◽  
Chun Ying Shen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Solid Loading ◽  
Zro2 Content ◽  
Zro2 Particle ◽  
Microstructure And Mechanical Properties ◽  
Dry Pressing ◽  
Gelcasting Process ◽  
Zirconia Toughened Alumina

Microstructure and mechanical properties of zirconia-toughened alumina (ZTA) composite ceramics prepared by gelcasting process were investigated. The results indicated that Al2O3-ZrO2 composites have high bending strength and fracture toughness for the solid loading of the suspension ³ 50vol.%. The bending strength and fracture toughness of sintered ZTA ceramics reach values as high as 631.5 MPa and 7.64 MPa·m1/2, respectively, with solid loading of suspension being 55vol.%. The t-ZrO2 content is increased, and the uniformity of ZrO2 particle distribution is improved in sintered samples prepared by gelcasting compared with those by dry pressing.

Mechanical Properties of GFRP Laminates Manufactured by Process Combined with Wet Lay-Up and Vacuum Curing

2006 ◽  
Vol 306-308 ◽  
pp. 845-850 ◽  
Author(s):  
Joong-Suk Kook ◽  
Tadaharu Adachi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Manufacturing Process ◽  
Volume Fraction ◽  
Optical Microscope ◽  
Bending Test ◽  
Complicated Structure ◽  
Structural Shape ◽  
Volume Fractions

In this study, a manufacturing process for glass fiber reinforced plastics (GFRP) laminates was developed to improve volume fraction of fibers and mechanical properties. The manufacturing process is combination with wet lay-up and vacuum curing under atmosphere pressure for production of large and complicated structure as a leisure boat and so on. Several kinds of GFRP laminates were produced to consider optimum conditions of the process from viewpoint of volume fraction of fibers and mechanical properties. Volume fractions of fibers in GFRP laminates were measured and cross sections were observed by an optical microscope. The volume fraction in the GFRP laminate made by the suggested method was improved to 41 %, although the one made by conventional wet lay-up method was 17.7 %. Because a lot of large voids included in the laminates were drastically decreased due to the methods. For each laminate, three-point bending test was performed to measure elastic modulus and fracture toughness. Elastic modulus was improved from 5.39 GPa to 8.91 GPa with high volume fractions of fibers. Fracture toughness was improved from 8.19 MPa m1/2 to 16.6 MPa m1/2. Therefore, it was obtained that the method combined with wet lay-up and vacuum curing is easy process for manufacturing large and complicated structure to improve excellent mechanical properties and accuracy of structural shape.

Mechanical properties of ion-implanted amorphous silicon

2004 ◽  
Vol 19 (1) ◽  
pp. 338-346 ◽  
Author(s):  
D.M. Follstaedt ◽  
J.A. Knapp ◽  
S.M. Myers
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Fracture Toughness ◽  
Finite Element ◽  
Elastic Modulus ◽  
Amorphous Silicon ◽  
Microelectromechanical Systems ◽  
Amorphous Structure ◽  
Alternative Material ◽  
Amorphous Si

We used nanoindentation coupled with finite element modeling to determine the mechanical properties of amorphous Si layers formed by self-ion implantation of crystalline Si at approximately 100 K. When the effects of the harder substrate on the response of the layers to indentation were accounted for, the amorphous phase was found to have a Young’s modulus of 136 ± 9 GPa and a hardness of 10.9 ± 0.9 GPa, which were 19% and 10% lower than the corresponding values for crystalline Si. The hardness agrees well with the pressure known to induce a phase transition in amorphous Si to the denser β–Sn-type structure of Si. This transition controls the yielding of amorphous Si under compressive stress during indentation, just as it does in crystalline Si. After annealing 1 h at 500 °C to relax the amorphous structure, the corresponding values increase slightly to 146 ± 9 GPa and 11.6 ± 1.0 GPa. Because hardness and elastic modulus are only moderately reduced with respect to crystalline Si, amorphous Si may be a useful alternative material for components in Si-based microelectromechanical systems if other improved properties are needed, such as increased fracture toughness.

scholarly journals Chemical and Mechanical Properties of Experimental Dental Composites as a Function of Formulation and Postcuring Thermal Treatment

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Renata A. Esteves ◽  
Letícia C. C. Boaro ◽  
Flávia Gonçalves ◽  
Luiza M. P. Campos ◽  
Cecy M. Silva ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Thermal Treatment ◽  
Flexural Strength ◽  
Low Cost ◽  
Chemical Properties ◽  
Degree Of Conversion ◽  
Dental Composites ◽  
Molar Ratios

This study evaluated the influence of formulation and thermal treatment on the degree of conversion, fracture toughness, flexural strength, and elastic modulus of experimental composites. Six composites were analyzed at BisGMA : TEGDMA molar ratios of 1 : 1 and 7 : 3 with filler at 30, 50, and 70 wt%. The degree of conversion was analyzed by Fourier transform infrared spectroscopy, fracture toughness was measured using the single-edge notched beam, and flexural strength and elastic modulus were measured with the 3-point bend test. For all tests, one-half of the specimens received thermal treatment at 170°C for 10 min. Data were analyzed by the Kruskal-Wallis or ANOVA/Tukey’s test (α = 5%). The 1 : 1 BisGMA : TEGDMA ratio showed higher properties than the 7 : 3 ratio. Although the material with 70% filler had a conversion lower than the one with 50%, it showed higher mechanical properties. The thermal treatment improved all properties in all materials. Therefore, the use of an equimolar ratio of BisGMA : TEGDMA can be paired with 70 wt% filler to design dental composites that possess increased advantageous physical and chemical properties. Furthermore, the simple and low-cost method of thermal treatment proposed for use in clinical dentistry has been shown to effectively improve the properties of all evaluated materials.

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