مجال
التميز
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تميز داسي وبحثي
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البحوث المنشورة
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البحث (1):
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عنوان البحث:
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Thermal
stability and field assisted sintering of cerium-doped YSZ ceramic
nanoparticles obtained via a hydrothermal process
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رابط إلى البحث:
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Click
here
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تاريخ النشر:
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14/08/2017
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موجز عن البحث:
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Owing
to its extraordinary range of properties, yttria-doped zirconia holds a
unique place among the ceramic oxide systems. To improve the properties for
some specific custom design applications, co-doping with other rare earth
oxides such as ceria is needed. The aim of this paper is to identify the
correlations between the phase composition evolution with increasing thermal
treatment temperature in order to establish the thermal stability in
connection with the ceria content and how does it influence the
yttria-stabilised zirconia microstructure. The ZrO2–3Y2O3–nCeO2 (n = 3, 6 and
9 wt.%) samples were obtained by a hydrothermal process and submitted to a
thermal treatment up to 1600 °C. Intensive characterization was performed via
X-ray powder diffraction and EDX analysis. It was found that up to 400 °C, a
monophasic structure was formed. At higher temperatures tetragonal zirconia
is formed as a major phase with the presence of secondary monoclinic and
cubic phases, depending on the Ce content and thermal treatment temperature.
Sintered compacts with densities up to 99.5% from the theoretical density
were obtained starting from the 6%CeO2–3%Y2O3–ZrO2- nanostructured powders
using a special field-assisted (FAST) sintering process. With increasing CeO2
content to 9% only, tetragonal zirconia with 6–9 nm crystallite sizes is
formed during the FAST sintering process.
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المؤتمرات العلمية:
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المؤتمر (1):
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عنوان المؤتمر:
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International
Conference on the Technology of Plasticity, ICTP
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تاريخ الإنعقاد:
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17/09/2017
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مكان الإنعقاد:
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Cambridge,
United Kingdom
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طبيعة المشاركة:
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Paper presentation
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عنوان المشاركة:
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Forming
of Miniature Components from Powders by Combining Field-activated Sintering
and Micro-Forming
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ملخص المشاركة:
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Micro-FAST
is a process concept which scales down conventional FAST to the micro-scale
process (dealing with miniature an micro-sized components) and it combines
the sintering process with a micro-forming process to enable shaping
components under coupled multi-fields actions and hence, to achieve
high-density, near-net-shaped components with high efficiency. The main
techniques developed for overcoming the barriers for the applications of FAST
at the miniature/micro-scales include: (i). Directly pressing/forming loose
powders in the die without using binders; (ii). Combining heating and shaping
to enable complex shapes/features; and (iii). Dedicatedly controlling fusion
bonding and material’s plastic flow to enable high-quality forming. Forming
from powders without using binders significantly shortened the process cycle,
which also led to high-purity of the parts formed; Combining forming and
sintering has led to high-density components produced as well as achieving
complex-shaped components; Large current density (e.g., >100~400 KA/cm-2)
enables very high heating rates and using small volumes of materials results
in high cooling rates, leading to much shorter forming/sintering cycles which
enables consolidation of micro/nanocomposites into bulk-sized components
while also preserving their micro/nanostructures.
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المؤتمر (2):
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عنوان المؤتمر:
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INTERNATIONAL
CONFERENCE ON SINTERING 2017
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تاريخ الإنعقاد:
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12/11/2017
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مكان الإنعقاد:
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SAN
DIEGO, CALIFORNIA. USA
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طبيعة المشاركة:
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Poster presentation
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عنوان المشاركة:
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Forming
micro components from ceramics materials by using FAST process
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ملخص المشاركة:
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Recent
studies have been undertaken to investigate the possibility of forming
micro-components by using the combination of microforming and
Electrical-field activated sintering (Micro-FAST). The FAST process uses low
voltage and high current, pressure-assisted sintering and synthesis
technique, which has been used recently in materials processing and
densification. This process shows the potential to produce solid parts from
ceramic powder materials with and without any binders. This method is similar
to hot pressing, but the mechanism of the heating and powder densification
are different. Using several type of ceramic powders (Al2O3, MSZ and ZrO2), a
number of processing parameters have been investigated, such as pressure,
heating rate, heating temperature and holding time, which helped to gain
optimum results The Ceramics powders were loaded directly into the die,
followed by electric-sintering under certain pressure. In this paper Ø4.00mm
× 4.00mm and Ø2.00mm × 2.00mm cylinder solid samples were produced. This
experiment was conducted by use of a Gleeble 3800 thermal- mechanical
simulator. Quite few properties of the solid samples, such as relative
density, hardness and the microstructures, were examined, and these showed
that good results have been found.
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المؤتمر (3):
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عنوان المؤتمر:
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Euspen:
Special Interest Group: Micro/Nano Manufacturing
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تاريخ الإنعقاد:
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8-9/11/ 2017
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مكان الإنعقاد:
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Glasgow,
UK
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طبيعة المشاركة:
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Poster presentation
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عنوان المشاركة:
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Forming
ceramics components using Micro-FAST
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ملخص المشاركة:
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There is an increased demand for miniature/micro
products (such as MEMS) and nanotechnology-based products (such as
nano-materials). However, Micro-manufacturing is, in fact, a link between the
Macro- and Nanomanufacturing and it is effective means to transfer
nanotechnology-products design into volume production.
The micro forming method is one of micro
manufacturing processes/methods, which has potential for low-cost, high volume
manufacturing. In order to meet the high demands on miniature products, a
rapid production technique and the system, high flexibility, cost efficiency
and processing a wide range of materials are needed.
Recent
studies have been undertaken to investigate the possibility of forming
micro-components by using the combination of micro- forming and
Electrical-field activated sintering (Micro-FAST). The FAST process uses low
voltage and high current, pressure-assisted sintering and synthesis
technique, which has been used recently in materials processing and
densification. The process shows the potential to produce solid parts from
ceramic powder materials with and without any binders. This method is similar
to hot pressing, but the mechanism of the heating and powder
densification are different. Several
types of ceramic powders with variable particle sizes have been formed
successfully. A number of processing parameters have been investigated, such
as pressure, heating rate, heating temperature and holding time, which helped
to gain optimum results. The Ceramics powders were loaded directly into the
die, followed by electric-sintering under certain pressure. In this work Ø4.00mm × 4.00mm and Ø2.00mm × 2.00mm cylinder solid samples were
produced. This experiment was conducted by using Gleeble 3800 thermal-
mechanical simulator. Quite few properties of the solid samples, such as
relative density, hardness and the microstructures, were examined, and these
showed that good results have been found.
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المؤتمر (4):
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عنوان المؤتمر:
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14th International conference on manufacturing
research 2016
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تاريخ الإنعقاد:
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6-8/09/2017
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مكان الإنعقاد:
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Loughborough.
UK
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طبيعة المشاركة 1:
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Paper
presentation
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عنوان المشاركة 1:
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Forming
Alumina (Al2O3) by Micro-FAST
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ملخص المشاركة 1:
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The Alumina (Al2O3), also known as Aluminium oxide,
has a good thermal conductivity, but it is an electrical insulator. The
Alumina is being used widely in the industry. Several research the sintering
of Alumina using the conventional hot pressing process or spark plasma
sintering (SPS). However, these methods are and have their own limits and
disadvantages, such as long process chains and low efficiency with the
processes and, rarely developed for the forming of miniature and micro-scale
components. In this study conducted in the report. A new process has been
used adapted from the electric-current activated sintering techniques (FAST)
and it is been combined with micro-forming technology and called the
(Micro-FAST). The Alumina powders were loaded directly into the die, followed
by electric-sintering under certain pressure. In this paper Ø4.00mm × 4.00 mm
and Ø2.00mm × 2.00 mm cylinder solid samples were produced. This experiment
was conducted by use of a Gleeble 3800 thermal- mechanical simulator. Several
properties of the solid samples, such as relative density, ESM and EDS, were
examined, and these showed good results have been obtained.
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طبيعة المشاركة2 :
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Paper
presentation
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عنوان المشاركة 2:
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Fabrication of Micro Components with MSZ Material
Using Electrical-Field Activated Powder Sintering Technology
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ملخص المشاركة2 :
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The electrical Field Activated Sintering Technology
(FAST) process uses low voltage and high current, pressure-assisted sintering
and synthesis technique, which has been used recently in materials
processing. This method can be used to densify materials and create
compounds, and it is similar to hot pressing, but the mechanism of the
heating and powder densification are different. In this paper an innovative
methodology has been adapted from the FAST process that can decrease the
volume of the components into micro scale and called (Micro- FAST). This
process is a rapid powder consolidation technology and shows the possibility
to produce solid parts from powder material. Using Magnesia- Stabilized
Zirconia (MSZ) powder material, several processing parameters have been
investigated, such as pressure, heating rate, heating temperature and holding
time, which helped to gain optimum results. In this paper Ø4.00mm × 4.00 mm
and Ø2.00mm × 2.00 mm cylinder solid samples were shaped. The SEM and EDS
have been conducted and the relative density has been examined and the
results showed a very good fabricated sample with 99.83% relative density.
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المؤتمر (5):
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عنوان المؤتمر:
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Workshop
On Smart Specialization And Advanced Materials For Extreme Condition
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تاريخ الإنعقاد:
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20-22/11/2017
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مكان الإنعقاد:
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Bucharest,
Romania
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طبيعة المشاركة:
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Poster
presentation
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عنوان المشاركة:
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Forming
Micro Ceramics Components By Using Fast Process
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ملخص المشاركة:
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There is an increased demand for miniature/micro
products (such as MEMS) and nanotechnology-based products (such as
nano-materials). The micro forming method is one of micro manufacturing
processes/methods, which has potential for low-cost, high volume manufacturing.
In order to meet the high demands on miniature products, a rapid production
technique and the system, high flexibility, cost efficiency and processing a
wide range of materials are needed.
Recently, many studies have been undertaken to
investigate the possibility of forming micro-components by using the
combination of micro- forming and Electrical-field activated sintering
(Micro-FAST). The FAST process uses low voltage and high current,
pressure-assisted sintering and synthesis technique, which has been used
recently in materials processing and densification. The process shows the
potential to produce solid parts from ceramic powder materials with and
without any binders. This method is similar to hot pressing, but the
mechanism of the heating and powder densification are different. Several types of ceramic powders with variable
particle sizes have been formed successfully. A number of processing
parameters have been investigated, such as pressure, heating rate, heating
temperature and holding time, which helped to gain optimum results. The
Ceramics powders were loaded directly into the die, followed by
electric-sintering under certain pressure. In this work Ø4.00mm × 4.00mm
and Ø2.00mm × 2.00mm cylinder solid
samples were produced. The properties
of the solid samples, such as relative density, hardness and the
microstructures, were examined, and these showed that good results have been
found.
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المؤتمر (6):
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عنوان المؤتمر:
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4th
International conference on new forming technology 2015
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تاريخ الإنعقاد:
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Glasgow, UK
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مكان الإنعقاد:
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6-9/08/2015
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طبيعة المشاركة 1:
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Paper presentation
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عنوان المشاركة 1:
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Forming of micro-components by electrical-field
activated sintering
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ملخص المشاركة1 :
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Recent research work has been undertaken to
investigate the feasibility of forming micro-components by combining
Electrical-field activated sintering and micro- forming (Micro-FAST). This
paper firstly introduces the Micro-Fast technology and experimental validation
method employed. Cylindrical components were used for the experiments and the
sintering and forming was realised by use of a Gleeble 3800 thermal-
mechanical simulator. Thirteen different types of powders (metallic and
ceramic) with variable particle sizes have been formed successfully. The
influential parameters, such as pressure, temperature and heating rate, were
studied. From the experiment results it is shown that the component quality
depends significantly on the pressure, the heating rate and maximum
temperature applied. Compared to other sintering technologies, the relatively
short forming-cycle time of Micro-Fast (increased heating rate and reduced
holding time) makes a good contribution to highly efficient particulate
sintering for micro-manufacturing.
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طبيعة المشاركة 2:
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Paper presentation
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عنوان المشاركة 2
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Fabrication of NiTi shape memory alloy by Micro-FAST
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ملخص المشاركة2 :
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A NiTi shape memory alloy, known as nitinol, has
been intensively studied for last five decades. The NiTi alloy with large
size is commonly produced by vacuum sintering, thermal explosion mode of
self-propagating high-temperature synthesis (TE- SHS) and spark plasma
sintering (SPS). These methods are, however, rarely utilized for the forming
of miniature and micro-sized components and have their own limits and
disadvantages, such as long process chains and low efficiency with the
processes. In the study reported in this paper, an innovation in rapid powder
consolidation technology, called Micro-FAST (combining micro-forming and
electric-current activated sintering techniques (FAST)) is introduced for the
forming of micro-components in which the loose powders are loaded directly
into the die, followed by electric-sintering. In the study, 4.0 mm × 4.0 mm
miniature cylinders were formed with pre-alloyed NiTi powders. Sintered
sample with relative density of 98.65% has been fabricated at a sintering
temperature of 1150 °C in a relatively short cycle time (119.5 s). Based on
the results of SEM and XRD, it was found that the densified samples with
Ni3Ti, NiTi and NiTi2 phases were produced.
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طبيعة المشاركة 3:
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Paper presentation
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عنوان المشاركة 3
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Forming of titanium and titanium alloy
miniature-cylinders by electrical-field activated powder sintering and
forming
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ملخص المشاركة 3:
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As demands on miniature products increase
significantly, a rapid process and production system for high-throughput,
highly flexible and cost-efficient volume production of miniaturised
components made from a wide range of materials is needed. A novel and
electrical-field-activated sintering and forming process shows the potential
to produce solid parts from powder material without any binder. Using
titanium (Ti) and titanium alloy (90Ti10Sn) powder material, several
processing parameters have been investigated, such as pressure, heating rate,
heating temperature and holding time, which helped to contribute to the
optimum result. In this study, using graphite dies, graphite punches and tungsten
carbide punches, solid samples were produced, having a cylinder shape of
Ø4.00 mm × 4.00 mm. Several properties of the solid Ti and 90Ti10Sn samples,
such as density, hardness and the microstructures, were examined, and these
showed that good results have been obtained.
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المؤتمر (7):
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عنوان المؤتمر:
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8th Saudi
Students’ Conference
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تاريخ الإنعقاد:
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31/01/2015
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مكان الإنعقاد:
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London,
UK
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طبيعة المشاركة:
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Poster participation
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عنوان المشاركة:
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Development
Of A New Process For Manufacturing Micro Parts By Using A Combination Of
Micro Forming And Fast Tecnology
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ملخص المشاركة:
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The
aim of this project is to develop a new fast forming process
configuration to manufacture miniature/micro components and corresponding tool-designs for machine setup enabling bulk-forming
from powder materials. The project involves a combination of micro forming
and Field Assisted Sintering Technology (FAST).
The
FAST process uses low voltage and high current, pressure-assisted sintering
and synthesis technique, which has been used recently in materials
processing. This method can be used to densify materials and synthesize
compounds, and it is similar to hot pressing, but the heating and powder
densification mechanism are different. Micro-FAST is a processing
technology which scales down conventional FAST process for small-length scale
manufacturing which involves a different sintering mechanism and tooling
technique, such as size-effect, electrical-thermo phenomena at micro-scale,
micro/nano-interfacial fusion bonding, tool-damages, etc.
Several
materials have been tested so far to produce different component-samples, and
more going to be done. The sintered samples are being analysed with a view to
optimising the process parameters to achieve optimal mechanical properties of
the formed parts. The analysis involves density, interface fusion,
microstructure and hardness analysis using weighting, (SEM), (EDS) and
micro-/nano-indentation techniques. The results will be used for the
guidance of developing an industrially viable process.
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المؤتمر (8):
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عنوان المؤتمر:
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9th Saudi Students’ Conference
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تاريخ الإنعقاد:
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13-14/02/2016
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مكان الإنعقاد:
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Birmingham,
UK
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طبيعة المشاركة:
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Poster
presentation
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عنوان المشاركة:
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Forming
Micro Components using Micro-FAST Technology
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ملخص المشاركة:
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There is an increased demand for miniature/micro
products, such as MEMS, micro- mechanical devices, micromedical components,
etc. Nanotechnology is also becoming more mature and influential, and many
nanotechnology- based products have been in the market such asnano-materials,
coated surfaces and nano-devices for communication, sensors, medical
implants/instruments. However, micro-manufacturing technology is an effective
means to transfer nanotechnology-products design into volume production. Micro-
manufacturing is, in fact, a link between the Macro- and Nano-manufacturing,
and this combination is very important for manufacturing miniature products.
There are many micro-manufacturing methods and
processes, one of those methods/processes being micro forming. It is a method
which has potential for low-cost, high volume manufacturing. In order to meet
the high demands on miniature products, a rapid production technique and the
system, high flexibility, cost efficiency and processing a wide range of materials
are needed.
Recent research work has been undertaken to examine
and investigate the feasibility of forming micro-components by combining the
microforming and Electrical-field activated sintering (Micro-FAST). The FAST
process uses low voltage and high current, pressure- assisted sintering and
synthesis technique, whichhas been used recently in materials processing.
This method can be used to densify materials and synthesize compounds, and it
is similar to hot pressing, but theheating and powder densification mechanism
are different. Micro-FAST is a processing technology which scales down
conventional FAST process for small-length scale manufacturing which involves
a different sintering mechanism and tooling technique, such as size-effect,
electrical-thermo phenomena at micro-scale, micro/nano-interfacial fusion
bonding, tool-damages, etc.
The formed components were used for the experiments
and the sintering and forming was recognized by using the Gleeble 3800
thermal-mechanical simulator. Several types of powders (metallic and ceramic)
with variable particle sizes have been formed successfully. The parameters,
such as pressure, temperature and heating rate, were studied. The results
from the experiment showed that the quality of component depends significantly
on the pressure, the heating rate and maximum temperature applied. Compared
to other sintering methods, Micro-FAST makes a good contribution to highly
efficient particulate sintering for micro-manufacturing due to the relatively
short forming-cycle time (increased heating rate and reduced holding time).
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