scholarly journals Nitrile Elastomer/LDH Composites with Varying Mg/Al Ratio, Curing, Nanoparticles Dispersion and Mechanical Properties

Author(s):  
Magdalena Lipińska
2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
S. H. Abdul Kaleel ◽  
Bijal Kottukkal Bahuleyan ◽  
J. Masihullah ◽  
Mamdouh Al-Harthi

Ethylene polymerization was carried out using highly active metallocene catalysts (Cp2ZrCl2and Cp2TiCl2) in combination with methylaluminoxane. Titanium (IV) oxide containing 1% Mn as dopant was used as nanofillers. The effects of filler concentration, reaction temperature, and pressure on the thermal and mechanical properties of polymer were analyzed. The improvement of nanoparticles dispersion in the polyethylene matrix was checked by WAXD. The thermal properties were analyzed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The filler impact on the melting temperature of polyethylene synthesized using Cp2ZrCl2was very minimal which is due to the degree of short-chain branching. The ash content was also analyzed for each nanocomposite and found to be in line with the activity of the catalyst. There was a significant increase in the mechanical properties of the polyethylene by addition of filler.


2010 ◽  
Vol 11 ◽  
pp. 113-118 ◽  
Author(s):  
Chang Woo Lee ◽  
Y.S. Shin ◽  
S.H. Yoo

The effect of SiC nanoparticle dispersion was investigated for microstructure change and mechanical properties of Sn-Bi electroplated alloys. The diameters of SiC nanoparticle in this study were 45-55 nm. The SiC nanoparticles were mixed with Sn-Bi electroplating and then the nanoparticles were dispersed with ultrasonic vibrator. After the dispersion, the SiC dispersed Sn-Bi alloys were electroplated on Cu deposited Si wafer. The microstructure and mechanical properties of the sample were evaluated by FE-TEM, FE-SEM, EDS, and shear tester. For TEM observation, the specimens were prepared by ultramicrotome and FIB. The SiC nanoparticles were well-dispersed in Sn-Bi alloy. SiC particles were located near grain boundaries or grain inside. The average grain size of the solder alloy was decrease about 30% compared with the grain size of Sn-Bi alloy prepared in the same condition. Due to the grain refinement and dispersion hardening by SiC nanoparticles, the SiC dispersed Sn-Bi alloy is expected to obtain high reliability and joining strength when it applied to interconnection materials.


2016 ◽  
Vol 825 ◽  
pp. 81-84
Author(s):  
Lenka Laiblová ◽  
Tomáš Vlach ◽  
Anuj Kumar ◽  
Alexandru Chira

Nanotechnology proved to be a useful tool that can significantly improve the mechanical properties of ultra-high performance concrete. This paper presents the results of a long-term research which is focused on the influence of SiO2 nanoparticles on the mechanical properties of high performance concrete. Three types of HPC specimens with a weight content of 0%, 1% and respectively 3% silica nanoparticle were prepared for flexural and compressive tests. SEM analysis was done in order to understand the effect of silica nanoparticle dispersion inside the cement matrix. The aim of this paper was to investigate the nanoparticles dispersion and how it affects concrete’s mechanical properties.


Author(s):  
S. Fujishiro

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.


Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).


Author(s):  
D. R. Clarke ◽  
G. Thomas

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.


Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.


Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.


Author(s):  
H.-J. Kleebe ◽  
J.S. Vetrano ◽  
J. Bruley ◽  
M. Rühle

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.


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