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| Articles
by
Faiz Ahmad |
Total Records (
11 ) for
Faiz Ahmad |
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Muhammad Rafi Raza
,
Faiz Ahmad
,
M.A. Omar
and
Ali S. Muhsan
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Austenitic 316L Stainless Steel (SS) is widely used in aerospace, automotive,
sports and medical industries due to its mechanical properties and corrosion
resistance. Defects free molding of parts depends upon the features of feedstock.
In powder injection molding, feedstock preparation is critical step and any
deficiency at this stage cannot be retrieve in latter steps. The objective of
this research work is to optimize solid loading for defects free injection molded
parts. During the present research work five formulations having solid loading
60-71 vol% were prepared by using multi component binder system. The degradation
temperature of feedstocks was determined by using Thermogravimetric analysis
(TGA) and flow behavior through rheometer. Homogeneity of the feedstock was
verified by using Scanning Electron Microscopy (SEM). Finally, injection molding
was done and it was found that the feedstocks having solid loading up to 69
vol% were successfully injection molded and components were without physical
defects. |
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W. Farhana Mohamad
,
Faiz Ahmad
and
Sami Ullah
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An intumescent fire retardant coating is a substance when exposed to fire,
it expands many time of its thickness forming as insulating layer of char which
is strong enough to protect steel structure from fire and retain the structural
integrity. Intumescent fire retardant coating has been developed by using Ammonium
Polyphosphate (APP), Expandable Graphite (EG), Melamine (MEL), Boric Acid, Bisphenol
A (BPA) and polyamide amine as a curing agent. Thus, local inorganic fillers
which are alumina (Al2O3), aluminum trihydrate-ATH (Al
(OH)3) and fumed silica added in the fire retardant materials. The
main objective of this paper is to investigate the effect of local inorganic
fillers on residual weight and char morphology of intumescent fire retardant
coating. Intumescent fire retardant coating with addition of alumina fillers
show greater residual weight and better char morphology. |
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Umar Patthi
,
Mokhtar Awang
,
Faiz Ahmad
,
Ahmad Majdi Abdul Rani
,
Norbert Ezinger
and
Andreas Hutter
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Friction Stir Welding (FSW) is a relatively new joining technique and the application
of the technique is still limited. Among the advantages of this method compared
to the conventional welding techniques is that it reduces problem associated
to metal re-solidification as the technique involves no melting stages. Such
advantages are especially applicable for joining high strength aerospace material
such as aluminium Metal Matrix Composite (MMC). In this study, the physical
and mechanical properties of Friction Stir Welding (FSW) on aluminium 6092/SiC25p/T6
was discussed and established. Weld characteristic was analyzed using SEM, EDX
and XRD, while mechanical properties were analyzed using Vickers hardness and
tensile test. Weld microstructure observation shows distribution of fine and
coarse particle cross the weld area. Microstructure analysis reveals difference
in redistribution of particles between the zones in the weld area, which consist
of the weld centre, advancing and retreating side of the tool. XRD results depict
insignificant difference of post weld stresses as well as maintained material
phases. The weld centre shows increase in hardness and an adequate retainment
of the material strength. In conclusion FSW causes changes in the material microstructure
due to the onset of plastic deformation and the post weld result shows it does
retain or even improve some of the material properties. |
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Mohd Azuwan Bin Maoinser
,
Faiz Ahmad
and
Muhammad Hatta Bin Mohd Junaidi
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Increasing usage of hybrid fiber composite in structural application such as
aircraft body has increased the drilling holes application to assemble the complex
structure. The objective of this study is to investigate the tensile properties
of hybrid fiber composite with the drilled holes. The samples were drilled using
the feed rate of 0.05 and 0.15 mm/rev and spindle speed of 690, 790, 1250, 1340,
2500 and 2700 rpm. The damage factor is analyzed using 3D non-contact machine
to study the effect of different drilling parameters on the drilled holes. The
correlation between damage factor and tensile results were studied in order
to observe the influence of damage factor on the tensile properties of the drilled
holes. In conclusion, the damage factor variations affected by different drilling
parameters do not have any influence on the tensile properties of hybrid fiber
composite with drilled holes. |
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Faiz Ahmad
,
M. Rafi Raza
,
A. Majdi Ab. Rani
and
S.H. Jason Lo
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In this study results of wear and friction coefficient of alumina particles reinforced Aluminium Matrix Composite (AMCs) were presented. The wear of AMCs was tested against the brake pad material under various loads ranging from 50 to 200 N at fixed speed of 600 rpm. A pin on-disk apparatus was used for measurement of wear rate of AMCs and resulting microstructure at each load was examined under scanning electron microscope. The coefficient of friction was also measured for corresponding loading conditions studied. Results showed an increased wear rate of AMCs with increased load and decrease in friction coefficient. Micro structural analysis of AMCs showed a combination of adhesive and abrasive types of wear for sample tested at loads. The reduction in coefficient of friction was noted as the surface of AMCs became rougher tested at higher load. This was related to the removal of alumina particles from the surface of AMCs during wear test at higher load that rough reduced coefficient of friction. |
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Sami Ullah
,
Faiz Ahmad
,
P.S.M. Megat-Yusoff
and
Nurul Hazwani binti Azmi
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Intumescent coating is an insulating system designed to decrease heat transfer from a fire to substrate structure to maintain its integrity. Zinc phosphate was used as primer coating on steel coupons for better protection from corrosion. The coating was based on Expandable graphite (EG), ammonium poly phosphate (APP), melamine, boric acid (B.A), bisphenol A epoxy resin BE-188 (BPA) and ACR Hardener H-2310 polyamide amine. Different formulations were developed to study the bonding of coating with steel substrate. The Intumescent coating was tested at 500°C for one h and it was found very stable and well bound with the steel substrate. Scanning Electron Microscope was used to study microstructure the substrate and bonding mechanism of coating with substrate after fire test. The results confirmed that coating was well bounded with steel substrate after fire test. |
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M. Rafi Raza
,
Faiz Ahmad
,
N. Ikram
,
R. Ahmad
and
A. Salam
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The wrought aluminum alloy 2219 was developed using an induction furnace followed by forging and hot rolling for the improvement of properties. Then the alloy was solution treated at 535°C for 48 min followed by water quenched and then aged at 210, 230 and 240°C for different time period. The maximum tensile strength of 411 MPa and hardness of 113.7 HV were achieved at 210°C after 4 h aging. The tensile strength of 368.12 MPa and hardness of 95.32 HV were obtained at 240°C after only 1.5 h aging time. The strength and hardness values of aged alloy specimens obtained in this work were reasonably higher (strength 51% and hardness 81%) than the specimens which were solution treated and quenched. Microstructures of the aged specimens also provided an evidence of dispersion of second phase precipitates particles in the single phase matrix. |
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Muhammad Rafi Raza
,
Faiz Ahmad
,
M.A. Omar
and
R.M. German
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This study reports the results of preparation of 316L stainless steel polymer based injection molded feed stock, rheology of feed stock and injection molding. The plastic binder was extracted from molded samples. The binder extraction was carried out in two steps: by solvent and thermal techniques. The results showed that feed stock prepared was suitable for injection molding and this was confirmed by rheology data measured by using capillary rheometer. The test samples were injection molded without physical defects. Paraffin Wax (major binder) was extracted by using solvent extraction for 300 min. The thermal debinding was performed four different heating rates rage 1-7°C min-1. The SEM results showed that the PW was completely extracted from the test samples after 300 min. |
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Sami Ullah
,
Faiz Ahmad
and
P.S.M. Megat-Yusoff
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In this study, we have discussed the thermal behaviour of intumescent coating. Intumescent coating is an insulating system designed to decrease heat transfer from a fire to substrate structure to maintain its integrity. The coating was based on Expandable Graphite (EG), Ammonium Poly Phosphate (APP), melamine, boric acid, kaolin clay (Al2Si2O5(OH)4), bisphenol. A epoxy resin BE-188 (BPA) and ACR hardener H-2310 polyamide amine as curing agent. Different formulations were developed to study the heat shielding effect. The C4 formulation showed better result on the heat shielding effect; it is further modified by adding kaolin clay 3-5 wt% in the next three formulations. Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) was done to study thermal analysis and char morphology of the formulations. The result showed that by adding the filler kaolin clay, the fire retardant time of coating was extended. The result showed that thermal behaviour of intumescent coating formulation was improved with 5 wt% of kaolin clay. |
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Ali S. Muhsan
,
Faiz Ahmad
,
Norani M. Mohamed
,
Putri S.M.BT M. Yusoff
and
M.R. Raza
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New thermal management solutions are required to provide cost-effective
means of dissipating heat from next generation microelectronic devices. In this
paper, fabrication of heat sink nanocomposite made of copper reinforced by multiwalled
carbon nanotubes up to 10 Vol. % using metal injection molding technique is
presented. A mixture of Cu-MWNTs was compounded using internal mixer machine
for homogenous dispersion of the solid powder in the binder. To ensure a flow
able feedstock during injection molding process, different binder systems and
their Cu-MWNTs feedstocks were examined using capillary rheometer machine. In
order to avoid binder degradation, TGA test was carried out. The TGA results
showed that the processing temperature such as mixing and injection molding
should be lower than 170°C. The injection molding was carried out at low
pressure. A combination of solvent and thermal debinding was used for binder
removal, and then the samples were isothermally sintered at different sintering
temperatures (900-1050°C) in argon atmosphere. The results showed that the
sintered samples experienced an isotropic shrinkage around 17% with relatively
homogeneous dispersion of MWNTs in the copper matrix which is expected to enhance
the physical and mechanical properties of the final product. |
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Faiz Ahmad
,
Sami Ullah
and
Muhammad Syahmi Hamizol
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Intumescent fire retarding coatings are designed to insulate
the substrate under the action of fire. In this research to study the effect
of Aluminium Trihydrate (ATH) and Fumed Silica (FS) on Expandable Graphite (EG)
Intumescent Fire Retardant Coating (IFRC). The IFRC was based on EG, Ammonium
Poly Phosphate (APP) as a acid source, melamine (MEL) as a blowing agent, Boric
Acid (BA) as additive, ATH, FS as inorganic fillers and bisphenol. A epoxy resin
BE-188 (BPA) was used as a binder with Hardener H-2310 polyamide amine. A range
of different formulations were developed to study the char expansion, morphology
of char and thermal properties of the IFRC. The formation of the final charring
layer and their morphological structures was studied by Scanning Electron Microscopy
(SEM). Char composition was determined by X-Ray Diffraction (XRD) technique.
Thermogravimetric Analysis (TGA) was used to study the thermal stability of
coating. Shear test was used to determine the bonding strength. IFRC with ATH
give a better performance than fumed silica with 4 wt.% of ATH gives the best
performance than others formulation in term of char expansion heat shielding,
char residual weight and boding strength. |
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