Dramatic improvement in mechanical properties of GNs-reinforced HDPE nanocomposites

2010 ◽  
pp. NA-NA
Author(s):  
Liwei Wang ◽  
Guohua Chen
Keyword(s):  
Mechanical Properties ◽  
Dramatic Improvement

Effect of Cu on Nanoscale Precipitation Evolution and Mechanical Properties of a Fe–NiAl Alloy

2017 ◽  
Vol 23 (2) ◽  
pp. 350-359 ◽  
Author(s):  
Qin Shen ◽  
Hao Chen ◽  
Wenqing Liu
Keyword(s):  
Mechanical Properties ◽  
Atom Probe Tomography ◽  
Diffusion Rate ◽  
Atom Probe ◽  
Peak Hardness ◽  
Dramatic Improvement ◽  
Number Density ◽  
Cu Alloy ◽  
Tension Tests ◽  
Nial Alloy

AbstractThe microstructural evolution of precipitation in two model alloys, Fe–NiAl and Fe–NiAl–Cu, was investigated during aging at 500°C for different times using atom probe tomography (APT). The APT results reveal that the addition of Cu effectively increases the number density of NiAl precipitates. This is attributed to Cu promoting the nucleation of NiAl particles by increasing the chemical driving force and decreasing the interfacial energy. The NiAl precipitates of the Fe–NiAl–Cu alloy grow and coarsen at a slower rate than that of the Fe–NiAl alloy, mainly due to the slower diffusion rate of the Cu atoms. The mechanical properties of the two alloys were characterized by Vickers hardness and tension tests. It was found that the addition of Cu results in the formation of core–shell precipitates with a Cu-rich core and a NiAl shell, leading to a dramatic improvement of peak hardness and strength. The effect of Cu on precipitation strengthening is discussed in terms of chemical strength and coherency strength.

Acoustically Coupled Microphone Arrays

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
R. N. Miles
Keyword(s):  
Mechanical Properties ◽  
Microphone Arrays ◽  
Dramatic Improvement ◽  
Small Animals ◽  
Noise Performance ◽  
Directional Response ◽  
Sound Sources ◽  
Acoustic Coupling ◽  
Back Volume ◽  
Acoustic Sensitivity

An analysis is presented of the performance benefits that can be achieved by introducing acoustic coupling between the diaphragms in an array of miniature microphones. The introduction of this coupling is analogous to the principles employed in the ears of small animals that are able to localize sound sources. Measured results are shown, which indicate a dramatic improvement in acoustic sensitivity, and noise performance can be achieved by packaging a pair of small microphones so that their diaphragms share a common back volume of air. This is also shown to reduce the adverse effects on directional response of mismatches in the mechanical properties of the microphones.

Effect of dc on the Formability of Ti–6Al–4V

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Carl D. Ross ◽  
Thomas J. Kronenberger ◽  
John T. Roth
Keyword(s):  
Mechanical Properties ◽  
Mechanical Loading ◽  
Electrical Current ◽  
Dramatic Improvement ◽  
Bulk Deformation ◽  
Resistive Heating ◽  
Applied Current ◽  
Designed Experiments ◽  
Compressive Loads ◽  
Current Densities

Recent research has demonstrated that the mechanical properties of metals are altered when an electrical current is passed through the material. These studies suggest that titanium alloys, due to their low formability and need for dramatic improvement, should be subjected to additional study. The research presented herein further investigates the use of electricity to aid in the bulk deformation of Ti–6Al–4V under tensile and compressive loads. Extensive testing is presented, which documents the changes that occur in the formability of titanium due to the presence of an electrical current at varying current densities. Using carefully designed experiments, this study also characterizes and isolates the effect of resistive heating from the overall effect due to the electrical flow. This study clearly indicates that electrical flow affects the material beyond that which can be explained through resistive heating. The results demonstrate that an applied electrical current within the material during mechanical loading can greatly decrease the force needed to deform the titanium while also dramatically enhancing the degree to which it can be worked without fracturing. Isothermal testing further demonstrates that the changes are significantly beyond that which can be accounted for due to increases in the titanium’s temperature. The results are also supported by data from tests using pulsed and discontinuously applied current. Furthermore, current densities are identified that cause an enhanced formability behavior to occur. Overall, this work fully demonstrates that an electrical current can be used to significantly improve the formability of Ti–6Al–4V and that these improvements far exceed that which can be explained by resistive heating.

Nature Nanocomposite Versus Man-Made Nanocomposites: Studies of Nanoscale Structural, Chemical and Mechanical Hierarchy of a Fish Scale in Contrast With Man-Made Polymer Nanocomposites

2013 ◽  
Author(s):  
D. Devaprakasam
Keyword(s):  
Mechanical Properties ◽  
Protective Layer ◽  
Living Organism ◽  
Sio2 Nanoparticles ◽  
Biological Properties ◽  
The Body ◽  
Dramatic Improvement ◽  
Fish Scale ◽  
Length Scales ◽  
Wide Range

Hierarchical designs of biological structures have remarkable physical, chemical mechanical and biological properties and functionalities over the wide range of length scales [1–4]. Man-made nanocomposites have dramatic improvement of the structural and mechanical properties but however they have very limited hierarchy [5]. Fish scales are bone-like tissues, which form a protective layer on the body of the fish and enable the fish to swim efficiently. Bones and bone-like parts in living organism are formed as tissues by self-assembly of bio-minerals and protein matrix. These tissues are bio-nanocomposites and have hierarchical structure ranging from nanoscale to macroscale [2–4]. Bio-hierarchy contains different bio-macromolecules, bio-minerals, interfacial bonds and porosity which result in gradient mechanical properties at multiple length scales [1–6]. Fish scale consists of inorganic bio-minerals and organic collagens [3,4]. Multilevel hierarchy influences elasticity, hardness and fracture toughness of fish scale. They have additional functions related to movement including reduction or increase of drag [7] and rapid manoeuvre while they are hunting or avoiding predators. In this article we report comparison studies of hierarchical nanocomposite of sardina pilchardus(sp) fish scale and man-made SiO2 nanoparticles filled nanocomposites.

The Statistical Approach to Study the Effects of the Size of Coarse Aggregates and Percentage of Steel Fiber on Mechanical Properties and Ductility of Concrete

2021 ◽  
Vol 1166 ◽  
pp. 95-112
Author(s):  
Seiyed Ali Haj Seiyed Taghia ◽  
Hamid Reza Darvishvand ◽  
Masood Ebrahimi ◽  
Elham Keramati
Keyword(s):  
Mechanical Properties ◽  
Statistical Approach ◽  
Steel Fiber ◽  
Aggregate Size ◽  
Fiber Content ◽  
Maximum Aggregate Size ◽  
Dramatic Improvement ◽  
Mean Values ◽  
Coarse Aggregates ◽  
Concrete Members

Concrete members are reinforced by steel fibers to overcome their brittle nature. This paper is focused on the effect of percentage of fiber and the maximum aggregate size on mechanical properties of concrete samples such as compressive and tensile strengths, and ductility. The mean values of these quantities show that by increasing the reinforcement content to 0.66% and the size to 12.5 mm, there is a dramatic improvement on properties of samples. Also, they demonstrate that the size of coarse aggregate has more effect on improvement of the quantities in comparison to steel fiber content and changing the size and fiber content has more effects on ductility than mechanical properties. Statistical approach which considers standard deviations of experimental data, confirms that the gravel regardless of fiber content, leads to the highest improvement on properties with size of 12.5 mm. But the results show for volumetric steel fiber without considering aggregate size, is 0.33%. This clearly indicates the effect of data scattering on mean values of mechanical properties and ductility.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

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%.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

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).

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

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.

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