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Science Forum Index » Nanotechnology Forum » Nanotech in Mechanical engineering
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| Sledgehammer |
 Posted: Wed Feb 15, 2006 2:27 pm |
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Can anyone explain is Nanotech applicable to mechanical engineering??.
I am a Equipment design engineer.
Thanx in advance.
Satish. |
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| LASPM |
| Posted: Wed Feb 15, 2006 6:27 pm |
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I'm also interested in the answer of this question.
Margareth
----- Original Message -----
From: "Sledgehammer" <satish.navaneethakrishnan@gmail.com>
Newsgroups: sci.nanotech
To: <sci.nanotech@nano-tek.org>
Sent: Wednesday, February 15, 2006 3:27 PM
Subject: [Sci.nanotech] Nanotech in Mechanical engineering
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| shaoping xiao |
| Posted: Wed Feb 15, 2006 11:07 pm |
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Based on my research, I know some applications
1) nanocomposites including nanotube and/or nanoparticle reinforced
composites
2) nanodevices including nanotube-based oscillators and gears etc.
shaoping
LASPM wrote:
--
================================================
Shaoping Xiao, PhD
Assistant Professor
Mechanical and Industrial Engineering &
Center for Computer Aided Design
2405 Seamans Center
College of Engineering
The University of Iowa
Iowa City, IA 52242-1527
Tel: (319) 335-6009 Fax: (319) 335-5669
Web: www.engineering.uiowa.edu/~sxiao |
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| Joy Dutta |
| Posted: Wed Feb 15, 2006 11:49 pm |
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Dear all,
The mechanical properties of nanostructured metals and alloys show dramatic
increases, which can be translated into reduced weight, or improved
performance for a platform. The Hall Petch equation relating tensile
strength to inverse grain size is well known, and the prediction from this
is that, as grain size is reduced the tensile strength will increase,
eventually to infinity!!!. However, the mechanisms governing the plastic
deformation of a nanostructured alloy are quite different from that of a
conventional alloy.
At grain sizes of a few nanometers, the normal processes of plastic
deformation by dislocation movement become irrelevant, as the grains are too
small to allow dislocation formation. New mechanisms including grain
boundary sliding and twinning become more important. The hardness and
strength of nanostructured iron , copper , aluminium does increase with
decreasing grain size, until a limit is reached. This depends on a metal ,
but is usually in the region of 50 nanometers or less , when the strength
starts to decrease again.
In ceramics, where dislocations are not mobile as in metals , plastic
deformation is very limited , and normally occurs only by grain boundary
sliding and diffusion at higher temperatures. These mechanisms are still
operative in nanostructured ceramics, but due to the extremely high grain
boundary area , and number density of triple junctions, deformation can
occur at much lower temperatures. Some ceramics and ceramic composites have
been " forged " isothermally at relatively low temperatures , which can lead
to more economic production , since the process in considerably faster than
conventional machining. Similarly super plasticity and reduced temperatures
has been demonstrated in some ceramics and nanostructured metal alloys ,
also due to enhanced grain boundary sliding. It has also been noted that the
wear resistance of nanostructured ceramics can be significantly better than
conventional ceramics.
The great interest in the mechanical behavior of nanostructured materials
originates from the unique mechanical properties first observed and/or
predicted for the materials prepared by the gas condensation method.
*Among these early observations/predictions were the following *
lower elastic moduli than for conventional grain size materials-by as
much as 30 - 50%**
very high hardness and strength-hardness values for nanocrystalline
pure metals
(~ 10 nm grain size) are 2 to 7 times higher than those of larger grained
(>1 m m) metals.**
a negative Hall-Petch slope, i.e., decreasing hardness with
decreasing grain size in the
nanoscale grain size regime.**
ductility-perhaps superplastic behavior at low homologous
temperatures in brittle ceramics or intermetallics with nanoscale grain
sizes, believed due to diffusional deformation mechanisms.**
While some of these early observations have been verified by subsequent
studies, some have been found to be due to high porosity in the early bulk
samples or to other artefacts introduced by the processing procedures.
I hope you will find this information useful
**
Dr. J. Dutta
Associate Professor Microelectronics and
Associate Dean
School of Engineering & Technology
Asian Institute of Technology
P.O. Box 4, Klong Luang, Pathumthani 12120 THAILAND
webpage: http://www.nano.ait.ac.th
e-mail:nano@ait.ac.th;
On 2/16/06, Sledgehammer <satish.navaneethakrishnan@gmail.com> wrote:
--
Dr. J. Dutta
Associate Dean
School of Engineering & Technology
Asian Institute of Technology
P.O. Box 4, Klong Luang
Pathumthani 12120, THAILAND
tel: +66-2-5245680
FAX: +66-2-5245697
Web: http://www.nano.ait.ac.th |
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| Phillip Huggan |
| Posted: Wed Feb 15, 2006 11:50 pm |
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The design of almost every metrology tool and manufacturing implement in
nanotech requires Mechanical Engineering expertise. I know some University
groups often custom build things like spin-coat machines and SPMs. I suspect
there is a good deal of Electrical Engineering involved too. Basically,
Chemical Engineers need tools built by Mechanical Engineers.
Also, incorporating nanotechnology enhancements to traditional Mechanical
Engineering processes is possible too. Chemical Vapor Deposition can be used
to coat drilling and abrasion surfaces with diamonds. There are always new
manufacturing technologies awaiting discover by clever Mechanical Engineers.
Composite wind turbines will be big in the future. The Space Elevator; an
envisioned CNT ribbon transporting payloads to space, cannot proceed without a
method of manufacturing low sidewall defect density CNTs. Again, new
manufacturing tools invented by Mechanical Engineers may hold the key.
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