Effect of Sintering Systems and Colloidal Silica Sols on the Mechanical Properties of Oriented Silica-Based Ceramic Core Materials

2010 ◽  
Vol 177 ◽  
pp. 418-420
Author(s):  
Jian Bo Yu ◽  
Zhong Ming Ren ◽  
B.Q. Wang ◽  
Y.W. Zhang

A series of silica -based ceramic cores sintered at 1150°C, 1200°C for different times were prepared, and this study compared the three-point bending strength of room temperature and 900°C with commercially available colloidal silica sols systems. Three-point bend specimens 60 × 10 × 4 mm were cast by vacuum hot pressing and tested in a special mechanical testing machine with high temperature test system of ceramics. The effect of sintering systems and colloidal silica sols on the mechanical properties of ceramic core was discussed. It could be concluded that specimens sintered at 1150°C for 5h have an obtainable maximum bending strength and those immersed in colloidal silica sols contents showed doubled bending strength in the present research.

2019 ◽  
Vol 27 (4(136)) ◽  
pp. 102-111
Author(s):  
Zbigniew Mikołajczyk ◽  
Katarzyna Pieklak ◽  
Aleksandra Roszak

Modern technical textiles, including knitted fabrics, are widely used in the construction industry. Regarding textiles in concrete reinforcement, methods based on shredded fibres, meshes, reinforcing mats, woven textiles and knitted DOStapes are frequently used as underlays of concrete constructions. Textiles are also used in the reinforcement of fibrous FRP composites. The research presented focused on producing composites made of MapeiMapefill concrete mass with reinforcement in the form of three variants of knitted meshes made of 228 tex polyamide threads, polypropylene threads of 6.3 tex and 203 tex glass threads, as well as identification of their mechanical properties. The mesh variant made of glass fibre is especially noteworthy, as its strength is more than three times higher than that of polyamide meshes. At the same time, a very small relative elongation of 3% is observed for this variant of knitted fabric, which is a desired property regarding the comparatively low stretching extension of concrete. In the process of making the composites, the adhesion of the concrete mass to the surface of the threads was analyzed. For this purpose, a "Sopro HE449" type agent was used. Composite beams were subjected to a three-point bending strength analysis on a testing machine. The results of strength measurements of the composites obtained prove that those with glass fibres demonstrate a threefold increase in strength compared to the original concrete beam.


Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3158 ◽  
Author(s):  
Santiago Cano ◽  
Tanja Lube ◽  
Philipp Huber ◽  
Alberto Gallego ◽  
Juan Alfonso Naranjo ◽  
...  

The fused filament fabrication (FFF) of ceramics enables the additive manufacturing of components with complex geometries for many applications like tooling or prototyping. Nevertheless, due to the many factors involved in the process, it is difficult to separate the effect of the different parameters on the final properties of the FFF parts, which hinders the expansion of the technology. In this paper, the effect of the fill pattern used during FFF on the defects and the mechanical properties of zirconia components is evaluated. The zirconia-filled filaments were produced from scratch, characterized by different methods and used in the FFF of bending bars with infill orientations of 0°, ±45° and 90° with respect to the longest dimension of the specimens. Three-point bending tests were conducted on the specimens with the side in contact with the build platform under tensile loads. Next, the defects were identified with cuts in different sections. During the shaping by FFF, pores appeared inside the extruded roads due to binder degradation and or moisture evaporation. The changes in the fill pattern resulted in different types of porosity and defects in the first layer, with the latter leading to earlier fracture of the components. Due to these variations, the specimens with the 0° infill orientation had the lowest porosity and the highest bending strength, followed by the specimens with ±45° infill orientation and finally by those with 90° infill orientation.


2007 ◽  
Vol 336-338 ◽  
pp. 1050-1052 ◽  
Author(s):  
Hai Tao Wu ◽  
Yun Long Yue ◽  
Wei Bing Wu ◽  
Hai Yan Yin

The γ-TiAl intermetallic compounds were produced at the temperature ranging from 850°C to 1050°C by the Spark Plasma Sintering (SPS) process. The effects of sintering temperature and holding time on the mechanical properties of γ-TiAl intermetallic compounds were investigated. The γ-TiAl intermetallic compounds sintered at 1050°C for 10 min showed a high relative density more than 98%, and had the best three-point bending strength of 643MPa, fracture toughness of 12 MPa·m1/2 and microhardness of 560MPa. The microstructural observations indicated typical characteristics of intergranular fracture, which meant the poor ductility of γ-TiAl intermetallic compounds.


2011 ◽  
Vol 275 ◽  
pp. 151-154 ◽  
Author(s):  
Yao Yao Ding ◽  
Tadafumi Adschiri ◽  
Garry A. Williams ◽  
Karen E. Callon ◽  
Maureen Watson ◽  
...  

Indentation is a mature technique that has been widely used in materials science to investigate the mechanical properties of metals and thin films. The indentation technique provides accurate modulus and hardness values of materials over many length scales and can target specific microstructures within heterogeneous materials. A more traditional engineering approach for mechanical properties is three point bend testing which provides an indication of the general fracture performance of the material. The breaking force and toughness results determined are based on the materials overall structure and composition. However, for both techniques, the testing specimen requires certain degree of process. This study evaluated a new indentation technique, which is able to penetrate biological tissues, apply compressive loads on the bone surface and record the resulting displacement, using wild type rats fed with a standard diet. In this study, both femurs from the same animal were tested followed by the three point bending to reach structural failure. We found a correlation between the two techniques and the properties of the bone in the animal model.


2007 ◽  
Vol 345-346 ◽  
pp. 1225-1228 ◽  
Author(s):  
Yoshinobu Shimamura ◽  
Atushi Yamamoku ◽  
Keiichiro Tohgo ◽  
Shigeru Tasaka ◽  
Hiroyasu Araki

Carbon nanofiller reinforced PLA was fabricated, and the mechanical properties and heat resistivity were measured. Vapor grown carbon fiber (VGCF) produced by Showa Denko K.K. was used for reinforcement, which has 150 nm in diameter and 10 μm in length. No surface treatment of VGCF was conducted. VGCF and PLA were compounded by using a twin screw extrusion machine and then pelletized. The weight fraction of VGCF ranged from 1wt% to 10wt%. Three point bending specimens were fabricated by using injection molding. At first, three point bending tests were carried out at room temperature. The bending stiffness increased from 3GPa to as high as 5GPa, but the bending strength slightly decreased. SEM observation of the fracture surfaces indicated pull-out of VGCFs over the fracture surfaces. These results imply that adhesion between VGCF and matrix was imperfect. Then, the heat deflection temperatures and glass transition temperatures of the specimens were measured. The addition of VGCF did not increase the glass transition temperature but slightly increased the heat deflection temperature.


2010 ◽  
Vol 434-435 ◽  
pp. 601-604 ◽  
Author(s):  
W. Yang ◽  
Y. Jiang ◽  
G.P. Zhang ◽  
Y.S. Chao ◽  
Xiao Wu Li

A sort of biological shells (Saxidomus purpuratus), which belongs to Bivalve, was selected as the target material, and hardness and dynamic three point bending fatigue tests were conducted to examine its mechanical properties. Microhardness measurements showed that the inner layer is the hardest. The indentation on the specimen with a lower bending strength was damaged more seriously by the same load. Three point bending fatigue tests demonstrated that this kind of the shells with a special structure comprising mineral and organic matrix can experience the repeated loads instead of immediate breaking. The fatigue results on a single shell investigated here indicated that the fatigue strength is usually less than the static bending strength. Most of the fatigue lives of the specimens are less than 2105 cycles. In addition, fatigue fracture surfaces are observed by scanning electron microscopy.


2018 ◽  
Vol 913 ◽  
pp. 522-528 ◽  
Author(s):  
Yong Wang ◽  
Kai Ming Cheng ◽  
Ji Xue Zhou ◽  
Wei Hong Li ◽  
Jin Huan Xia

In this paper, magnesium matrix composite with different AlN particles content were fabricated by powder metallurgy. The microstructure of composites was investigated by scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM). The mechanical properties of composites were measured by electronic universal testing machine. The results show that the best densification and the highest mechanical properties of composites reached when the addition of 6wt.% reinforcement at 620 °C for 1 hour. Additionally, the compressive strength and bending strength of composites were 217.06 MPa and 207.40 MPa respectively, increased by 79.2% and 91.12% compared with matrix alloy, and the reinforcement particles uniformly distributed in the matrix alloy. It may be concluded that the strengthening mechanism of composites is mainly attributed to grain refinement, load transfer, and dislocation strengthening.


2012 ◽  
Vol 624 ◽  
pp. 264-268 ◽  
Author(s):  
Duo You Zhang ◽  
Peng Liu ◽  
Chun Fa Ouyoung ◽  
Qun Gao ◽  
Kang Sheng Zheng ◽  
...  

PNA012 is a new nucleating agent on polybutylene terephthalate. The effect of different dosage of PNA012 on crystallization and mechanical properties were investigated by means of differential scanning calorimetry, universal testing machine, melt flow indexer and vicat softening testing machine. It was revealed that the PNA012 could substantially accelerate the crystallization of PBT. Compared with the pure PBT,the crystallization temperature of PBT/PNA012 rises from 196.3 °C to 199.7 °C and crystallization degree from 34.2% to 39.9%. The tensile Strength of PBT/PNA012 is increased 9.7%. The Bending Strength has a rise of 9.3% and the heat distortion temperatures of PBT/PNA012 is increased from 115.07°C to 125.94°C.


2012 ◽  
Vol 567 ◽  
pp. 146-149 ◽  
Author(s):  
Xue Mei Fan ◽  
Jian Feng Wang ◽  
Cheng Jin Duan ◽  
Xiang Xin Xia ◽  
Zhao Hui Wang

In order to analyze the mechanical properties of Carbon/epoxy facings-Aluminum honeycomb sandwich structure, we simulated panels of different layers and core thickness using ABAQUS finite element analysis program. And three-point bending tests and shear tests were made on the same panels using electronic universal testing machine. In addition, we also made the same three-point bending tests on steel tubes to get a comparison with honeycomb sandwich panels. It could be seen that, the simulated results were basically identified with experimental results. The results indicated that core thickness played an important role in the panels’ bulking modulus, and number of carbon fiber layers decided the shear strength. As a whole, honeycomb sandwich structure was suitable for use in the car body with good mechanical properties under premise of lighter.


2014 ◽  
Vol 602-603 ◽  
pp. 586-589
Author(s):  
Bing Sun ◽  
Bing Bing Fan ◽  
Chen Yang Wang ◽  
Bin Bin Wang ◽  
Wen Li ◽  
...  

In this study, glassy phase is formed by SiO2-K2O addition to serve as amorphous grain boundary transition layer. SiC (SiO2-K2O) / Cu composite material were prepared by two-step coating method and hot pressing sintered below 770°C, 30MPa for 1.5h, using α-SiC as main reinforced phase, SiO2-K2O as grain boundary and Cu as matrix. The Cu-SiC volume ratio was 75:25. The SiO2contents were 5vol.%, 10vol.%, 15vol.%, 20vol.% and 25vol.% of the total volume of the SiC / Cu. XRD and SEM techniques were used to characterize the composite particles and the sintered compacts; Archimedes method, Vickers hardness tester, universal testing machine to test the apparent porosity of the composite materials, the Vickers hardness and the bending strength, respectively. The results showed that with increasing of glassy phase contents, the Vickers hardness and the bending strength first rise and then drop, at the same time, it shows the opposite tendency for the apparent porosity. The sintering samples with the SiO2content of 15vol.% have the optimum mechanical properties, the Vickers hardness reached 1.49 GPa, and the bending strength was close to 235 MPa.


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