scholarly journals The Influence of Fly Ash on Mechanical Properties of Clay-Based Ceramics

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 930
Author(s):  
Tomáš Húlan ◽  
Igor Štubňa ◽  
Ján Ondruška ◽  
Anton Trník

Elastic properties of mixtures of illitic clay, thermal power plant fly ash (fluidized fly ash—FFA and pulverized fly ash—PFA), and grog were investigated during the heating and cooling stages of the firing. The grog part in the mixtures was replaced with 10, 20, 30, and 40 mass% of the fly ash, respectively. The temperature dependence of Young’s modulus was derived using the dynamical thermomechanical analysis, in which dimensions and mass determined from thermogravimeric and thermodilatometric results were used. Flexural strength was measured at the room temperature using the three-point bending test. The following results were obtained: (1) Bulk density showed a decreasing trend up to 900 °C and a steep increase above 900 °C. During cooling, the bulk density slightly increased down to the room temperature. (2) Young’s modulus increased significantly during heating up to ~300 °C. Dehydroxylation was almost not reflected in Young’s modulus. At temperatures higher than 800 °C, Young’s modulus began to increase due to sintering. (3) During cooling, down to the glass transformation, Young’s modulus slightly increased and then began to slightly decrease due to microcracking between phases with different thermal expansion coefficients. (4) Around the β→α quartz transition, radial stresses on the quartz grain altered from compressive to tensile, creating microcracks. Below 560 °C, the radial stress remained tensile, and consequently, the microcracking around the quartz grains and a decreasing Young’s modulus continued. (5) With a lower amount of PFA and FFA, a higher Young’s modulus was reached after sintering. The final values of Young’s modulus, measured after firing, show a decreasing trend and depend linearly on the part of fly ash. (6) The flexural strength measured after firing decreased linearly with the amount of the fly ash for both mixtures.

2011 ◽  
Vol 484 ◽  
pp. 98-101
Author(s):  
Yasushi Okuzono ◽  
Yoshihiro Hirata ◽  
Naoki Matsunaga ◽  
Soichiro Sameshima

The compressive stress-strain relation (room temperature) of SiC compact (75 vol% 800 nm SiC- 25 vol% 30 nm SiC) hot-pressed with 1.6 vol% Al2O3- 0.83 vol% Gd2O3 at 1950 °C was examined at a crosshead speed of 0.05 mm/min. The dense SiC (97.8 ± 1.5 % theoretical density) possessed 796 MPa of average flexural strength, 5.27 MPa・m1/2 of fracture toughness, 8.1 of Weibull modulus, and 475 GPa of average flexural Young’s modulus. The strains of SiC compacts along directions of height and width changed nonlinearly with applied compressive stress. The apparent Young’s modulus and Poisson’s ratio decreased with increasing strain along the direction of height and reached constant values of 275 ± 59 GPa and 0.214 ± 0.05, respectively. The steady-state compressive Young’s modulus was independent of the flexural strength.


2007 ◽  
Vol 353-358 ◽  
pp. 1471-1474 ◽  
Author(s):  
Chen Su ◽  
Gao Hui Wu ◽  
Jing Qiao ◽  
Long Tao Jiang

The graphite/2024Al composites have been fabricated by improved Squeeze Exhaust Casting (SQEC) method. Two kinds of graphite preforms with porosities of 13% and 17% respectively were infiltrated with 2024Al (Al-5Cu-2Mg) alloy under the pressure of 73MPa. The disadvantages of traditional Squeeze Casting (SQC) were avoided and the distribution of aluminum alloy appeared homogenous 3D network in the composites. Flexural strength and Young’s modulus were determined at room temperature. Compared to graphite preform, the composites exhibited a significant enhancement of mechanical properties. The flexural strength and Young’s modulus of X-Y direction of G186/2024Al composites increased from 38.6MPa to 99.7MPa and from 10.1GPa to 19.7GPa, respectively. The fracture mechanism of the composites was discussed on the basis of fracture surfaces.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4968
Author(s):  
Tomáš Húlan ◽  
Igor Štubňa ◽  
Ján Ondruška ◽  
Štefan Csáki ◽  
František Lukáč ◽  
...  

Dynamical thermomechanical analysis of 5 illite-based clays from deposits in Slovakia, Estonia, Latvia, and Hungary is presented. The clays consist of illite (37–80 mass%), quartz (12–48 mass%), K-feldspar (4–13 mass%), kaolinite (0–18 mass%), and calcite (0–3 mass%). Young’s modulus is measured during the heating and cooling stages of firing (25 °C → 1100 °C → 25 °C). The liberation of the physically bound water increases Young’s modulus by ∼70% for all studied clays. By increasing the temperature, dehydroxylation and the α → β transition of quartz take place without a significant effect on Young’s modulus. Sintering, which starts at 800 °C, leads to an intensive increase in Young’s modulus up to the highest temperature (1100 °C). The increase remains also in the early stage of cooling (1100 °C → 800 °C). This increase of Young’s modulus is also the result of solidification of the glassy phase, which is finished at ∼750 °C. A sharp minimum of Young’s modulus is observed at around the β → α transition of quartz. Then, Young’s modulus still decreases its value down to the room temperature. The physical processes observed during heating and cooling do not differ in nature for the studied clays. Values of Young’s modulus vary at around 8 GPa, up to 800 °C. During sintering, Young’s modulus reaches values from 30 GPa to 70 GPa for the studied clays. The microstructure and composition given by the origin of the clay play a cardinal role for the Young’s modulus of the final ceramic body.


2003 ◽  
Vol 782 ◽  
Author(s):  
Wen-Hsien Chuang ◽  
Thomas Luger ◽  
Rainer K. Fettig ◽  
Reza Ghodssi

ABSTRACTMechanical properties of micro-electro-mechanical systems (MEMS) materials at cryogenic temperatures are investigated to extend MEMS devices into space applications. A helium-cooled measurement setup mimicking the outer space environment is developed and installed inside a focused-ion-beam (FIB) system. T-shape, low-stress LPCVD silicon nitride cantilevers suspended on a silicon substrate are fabricated as the test structures using bulk micromachining technique. A lead-zirconate-titanate (PZT) translator and a silicon diode are utilized as an actuator and a temperature sensor in the measurement setup, respectively. The resonant frequencies of an identical cantilever with different “milling masses” are measured to obtain the thickness and the Young's modulus. Additionally, a bending test is performed to determine the fracture strength. From the experiments, the Young's modulus of LPCVD silicon nitride thin films varies from 260.5 GPa ± 5.4 GPa at room temperature (298 K) to 266.6 GPa ± 4.1 GPa at 30 K, while the fracture strength ranges from 6.9 GPa ± 0.6 GPa at room temperature to 7.9 GPa ± 0.7 GPa at 30 K.


2015 ◽  
Vol 35 (3) ◽  
pp. 257-266 ◽  
Author(s):  
Rahim Eqra ◽  
Kamal Janghorban ◽  
Habib Daneshmanesh

Abstract Because of extraordinary physical, chemical and mechanical properties, graphene nanosheets (GNS) are suitable fillers for optimizing the properties of different polymers. In this research, the effect of GNS content (up to 1 wt.%) on tensile and flexural properties, morphology of fracture surface, and toughening mechanism of epoxy were investigated. Results of mechanical tests showed a peak for tensile and flexural strength of samples with 0.1 wt.% GNS such that the tensile and flexural strength improved by 13% and 3.3%, respectively. The Young’s modulus and flexural modulus increased linearly with GNS content, although the behavior of the Young’s modulus was more remarkable. Morphological investigations confirmed this behavior because the GNS dispersion in the epoxy matrix was uniform at lower contents and agglomerated at higher contents. Finally, microscopical observation showed that the major toughening mechanism of graphene-epoxy nanocomposites was crack path deflection, which changed the mirror fracture surface of the pure epoxy to rough surface.


2008 ◽  
Vol 19 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Rafael Leonardo Xediek Consant ◽  
Erica Brenoe Vieira ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
João Neudenir Arioli-Filho

This study evaluated the effect of microwave energy on the hardness, impact strength and flexural strength of the Clássico, Onda-Cryl and QC-20 acrylic resins. Aluminum die were embedded in metallic or plastic flasks with type III dental stone, in accordance with the traditional packing technique. A mixing powder/liquid ratio was used according to the manufacturer's instructions. After polymerization in water batch at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling at room temperature, and submitted to finishing. Specimens non-disinfected and disinfected by microwave irradiation were submitted to hardness, impact and flexural strength tests. Each specimen was immersed in distilled water and disinfected in a microwave oven calibrated to 650 W for 3 min. Knoop hardness test was performed with 25 g load for 10 s, impact test was carried out using the Charpy system with 40 kpcm, and 3-point bending test with a crosshead speed of 0.5 mm/min until fracture. Data were submitted to statistical analysis by ANOVA and Tukey's test (?=0.05). Disinfection by microwave energy decreased the hardness of Clássico and Onda-Cryl acrylic resins, but no effect was observed on the impact and flexural strength of all tested resins.


2013 ◽  
Vol 761 ◽  
pp. 83-86
Author(s):  
Hideaki Sano ◽  
Junichi Morisaki ◽  
Guo Bin Zheng ◽  
Yasuo Uchiyama

Effects of carbon nanotubes (CNT) addition on mechanical properties, electric conductivity and oxidation resistance of CNT/Al2O3-TiC composite were investigated. It was found that flexural strength, Young’s modulus and fracture toughness of the composites were improved by addition of more than 2 vol%-CNT. In the composites with more than 3 vol%-CNT, the oxidation resistance of the composite was degraded. In comparison with Al2O3-26vol%TiC sample as TiC particle-percolated sample, the Al2O3-12vol%TiC-3vol%CNT sample, which is not TiC particle-percolated sample, shows almost the same mechanical properties and electric conductivity, and also shows thinner oxidized region after oxidation at 1200°C due to less TiC in the composite.


1986 ◽  
Vol 108 (2) ◽  
pp. 141-148 ◽  
Author(s):  
H. C. Park ◽  
Y. K. Liu ◽  
R. S. Lakes

The elastic Young’s modulus and shear modulus of bone-particle impregnated polymethylmethacrylate (PMMA) has been measured experimentally at room temperature as a function of bone particle concentration. It was found that the moduli increased with increasing bone particle content. This increase was less than the stiffness increase predicted by higher-order composite theory [1, 2] under the assumption of perfect bonding between particles and matrix. It was concluded that a bond existed but that it was not a perfect bond.


2021 ◽  
Vol 32 (2) ◽  
pp. 87-104
Author(s):  
Pui-Voon Yap ◽  
Ming-Yeng Chan ◽  
Seong-Chun Koay

This research work highlights the mechanical properties of multi-material by fused deposition modelling (FDM). The specimens for tensile and flexural test have been printed using polycarbonate (PC) material at different combinations of printing parameters. The effects of varied printing speed, infill density and nozzle diameter on the mechanical properties of specimens have been investigated. Multi-material specimens were fabricated with acrylonitrile butadiene styrene (ABS) as the base material and PC as the reinforced material at the optimum printing parameter combination. The specimens were then subjected to mechanical testing to observe their tensile strength, Young’s modulus, percentage elongation, flexural strength and flexural modulus. The outcome of replacing half of ABS with PC to create a multi-material part has been examined. As demonstrated by the results, the optimum combination of printing parameters is 60 mm/s printing speed, 15% infill density and 0.8 mm nozzle diameter. The combination of ABS and PC materials as reinforcing material has improved the tensile strength (by 38.46%), Young’s modulus (by 23.40%), flexural strength (by 23.90%) and flexural modulus (by 37.33%) while reducing the ductility by 14.31% as compared to pure ABS. The results have been supported by data and graphs of the analysed specimens.


2011 ◽  
Vol 8 (2) ◽  
pp. 551-560
Author(s):  
Baghdad Science Journal

In this study, composite materials were prepared using unsaturated polyester resin as binder with two types of fillers (sawdust and chopped reeds). The molding method is used to prepare sheets of UPE / sawdust composite and UPE / chopped reeds composite. The mechanical properties were studied including flexural strength and Young's modulus for the samples at normal conditions (N.C). The Commercial wood, UPE and its composite samples were immersed in water for about 30 days to find the weight gain (Mt%) of water for the samples, also to find the effect of water on their flexural strength and Young's modulus. The results showed that the samples of UPE / chopped reeds composite gained highest values of flexural strength (24.5 MPa) and Young's modulus (5.1 GPa) as compared with other composites at (N.C). The results showed that the wet samples of sawdust composite have lowest values of weight gain (Mt %) of water (0.043%) as compared with other composites after immersion. Also it’s showed a slight decrease in values of Young's modulus for all the samples after immersion as compared with the samples at (N.C). Finally it’s showed a slight decrease in values of flexural strength for all the samples except for the composite material formed from UPE / chopped reeds which showed an increase in the value of flexural strength after immersion, where the wet samples of UPE / chopped reeds composite gained (29 MPa) as compared with the samples at (N.C).


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