Faiz Ahmad - Academia.edu (original) (raw)

Papers by Faiz Ahmad

This study was conducted to evaluate the effects of elemental boron on densification of 316L stai... more This study was conducted to evaluate the effects of elemental boron on densification of 316L stainless steels. Elemental nano size boron (nB) powder of 0.5, 1 and 1.5 wt. % was blended with 316L SS to produce homogeneous feedstock for low pressure powder injection molding (LPIM) process. LPIM molded samples were sintered at 12300C using high vacuum 10-5Torr. The Results showed that addition of elemental boron has favorable effects on densification. Addition of 0.5 wt% nano size elemental boron in 316L SS has enhanced densification up to 98.5%. Defect free gears were injection molded and sintered successfully using optimal sintering cycle.

MATEC Web of Conferences, 2014

Thermal conductivity of carbon nanotubes (CNTs) copper-matrix nanocomposites was predicted by usi... more Thermal conductivity of carbon nanotubes (CNTs) copper-matrix nanocomposites was predicted by using numerical approach. In the present study, twenty representative volume elements (RVEs) were modeled by assuming that the CNTs are distributed homogeneously in the copper (Cu) matrix. It is assumed that each RVE contains different pattern of CNTs distribution while the direction, diameter and length of CNTs are held constant. The effect of the CNTs-matrix interfacial resistance was also negligible. Therefore, it was observed that the predicted values of thermal conductivity would reach to the upper-bound rule of mixtures.

MATEC Web of Conferences, 2014

Due to the rapid growth of high performance electronics devices accompanied by overheating proble... more Due to the rapid growth of high performance electronics devices accompanied by overheating problem, heat dissipater nanocomposites material having ultra-high thermal conductivity and low coefficient of thermal expansion was proposed. In this work, a nanocomposite material made of copper (Cu) reinforced by multi-walled carbon nanotubes (CNTs) up to 10 vol. % was prepared and their thermal behaviour was measured experimentally and evaluated using numerical simulation. In order to numerically predict the thermal behaviour of Cu/CNTs composites, three different prediction methods were performed. The results showed that rules of mixture method records the highest thermal conductivity for all predicted composites. In contrast, the prediction model which takes into account the influence of the interface thermal resistance between CNTs and copper particles, has shown the lowest thermal conductivity which considered as the closest results to the experimental measurement. The experimentally measured thermal conductivities showed remarkable increase after adding 5 vol.% CNTs and higher than the thermal conductivities predicted via Nan models, indicating that the improved fabrication technique of powder injection molding that has been used to produced Cu/CNTs nanocomposites has overcome the challenges assumed in the mathematical models.

International Journal of Applied Physics and Mathematics, 2011

In this study, the flow behavior of multi-walled carbon nanotubes (CNTs) reinforced copper matrix... more In this study, the flow behavior of multi-walled carbon nanotubes (CNTs) reinforced copper matrix feedstocks is presented. The solid loadings in the copper feedstock were investigated in the ranges of 55-61 Vol. % using binder. Pure copper (Cu) and Cu/CNTs feedstocks were compounded using internal mixer machine for homogenous dispersion of solids in the binder. The flow behavior was measured using a capillary rheometer in the shear rate range expected to occur during powder injection molding. An acceptable increasing trend in viscosity of the copper feedstock with powder loading was recorded. Cu/CNTs composite feedstocks showed viscosity more than 1000 Pa.s which is most probably due to the addition of CNTs and increasing trend in viscosity of Cu/CNTs was noted as well. The results also identified that the feedstock containing 59 vol. % copper was most suitable for substitution of CNTs in Cu feedstock.

Applied Mechanics and Materials, 2013

Carbon nanotubes (CNTs) reinforced copper (Cu) matrix nanocomposites prepared via advanced fabric... more Carbon nanotubes (CNTs) reinforced copper (Cu) matrix nanocomposites prepared via advanced fabrication method is presented. Functionalization and ultrasonication processes have been applied to enhance the dispersion of purified CNTs and creates sidewalls groups that have the potential to bond CNTs to the metal matrix. The main part of this approach was metal injection molding (MIM) technique, which is a combination of powder metallurgy and plastic injection molding technique. Preparation of MIM feedstock required a melting and mixing process of binder system (polymers) with the solid loading, which has been carried out using a twin screw rotor machine. This machine provides a viscous media of the molten binder with high shear forces that allow the additives (carbon nanotubes/copper powder) to be mixed properly and exfoliate the CNTs clusters with uniformdispersion inside the Cu matrix. Subsequently, to prove our expected results, observation tests of TEM, SEM, FESEM and CNTS were em...

Procedia Engineering, 2016

Dolomite Clay was introduced in a traditional intumescent flame retardant system which contains a... more Dolomite Clay was introduced in a traditional intumescent flame retardant system which contains ammonium polyphosphate/expandable graphite/melamine (APP-EG-MEL) to evaluate its effects on char morphology and fire performance. The effect of dolomite clay on the fireresistance and thermal properties of expandable graphite based Intumescent fire retardant coatings has been investigated by using Bunsen burner fire test and thermal gravimetric (TG) techniques. The current study describes the effects of Dolomite Clay on the heat shielding performance of intumescent passive fireproofing coatings during fire testing. The fire performance of dolomite clay reinforced intumescent coating formulations were evaluated by Bunsen burner fire test according to ASTM E-119. Results showed that the dolomite reinforcement in IFRC formulation significantly reduced the steel substrate temperature up to 180 °C after 1 hour of fire exposure. The coating degradation was studied using thermogravimetric analysis (TGA). The physical morphology and alignment of intumescent char residue were studied by field emission scanning electron microscopy (FESEM). TGA analysis revealed that IFD (8) containing 8 wt. % of dolomite clay enhanced residual weight by 37.30%. It is suggested that Dolomite clay can enhance the fire performance and can significantly affect the formation of dense and continuous char if incorporated as a filler in conventional intumescent fire resistive systems.

Metal Powder Report

Ni-Mo-TiC samples were prepared from powder and vacuum hot pressed. The specimens were heated to ... more Ni-Mo-TiC samples were prepared from powder and vacuum hot pressed. The specimens were heated to melting in microgravity conditions. The structures are shown to consist of globular TiC particles in a Ni-Mo matrix and the distributions of elements were determined by Auger spectroscopy. It is suggested that thermal convection and gravity segregation were absent as a result of microgravity processing.

Progress in Organic Coatings

International Journal of Powder Metallurgy, 2008

Applied Mechanics and Materials, Jul 16, 2014

Drill point angle of twist drill has a significant effect on thrust force and delamination factor... more Drill point angle of twist drill has a significant effect on thrust force and delamination factor on drilled holes in fiber reinforced polymer (FRP) composites. In this study, three drill point angle of twist drill; 85°, 118° and 135° were used to drill holes in hybrid fiber reinforced polymeric composite (HFRP). HFRP composites were fabricated using vacuum infusion molding (VIM) technique. The test samples were cured at 90°C for two hours. In drilling process various drill point angle and feed rate were employed to investigate the effect of both parameters on thrust force and delamination factor when drilling the HFRP composite. The results showed that small drill point angle and low feed rate can reduce the thrust force leading to the reduction of damage factor at the hole's entrance and exit.

International Journal of Powder Metallurgy, 2006

Résumé/Abstract Optimum machine molding parameters were identified and defect-free moldings of Si... more Résumé/Abstract Optimum machine molding parameters were identified and defect-free moldings of SiC-reinforced aluminum alloy matrix composites (AMCs) were produced by powder injection molding (PIM). Fiber orientation was characterized qualitatively. Highly ...

MATEC Web of Conferences, 2014

Various types of intumescent fire retardant coatings (IFRC's) have been used to protect the subst... more Various types of intumescent fire retardant coatings (IFRC's) have been used to protect the substrates exposed to fire. In current study, high temperature filler Wollastonite (W) filler was used to improve fire performance of intumescent fire retardant coating. The basic ingredients of the coating were ammonium poly-phosphate (APP) as acid source, expandable graphite (EG) as carbon source, melamine (MEL) as blowing agent in epoxy binder, boric acid as additive and hardener as curing agent. In this study a range of coating formulations were developed by using different weight percentages of Wollastonite filler. The coated steel substrate samples were tested for fire performance using Bunsen burner and char expansion was measured using furnace fire test. Composition of the char was determined by X-ray diffraction (XRD) technique. The char morphology was studied using field emission scanning electron microscopy (FESEM). Results showed that Intumescent coating with addition of Wollastonite filler enhanced anti-oxidation of the char. Presence of phosphorus, calcium and silicon in char layer further improved the thermal stability of char. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net.

Nanoscience and Nanotechnology Letters, 2014

Carbon nanotubes (CNTs) with its exceptional thermal and mechanical properties hold the promise o... more Carbon nanotubes (CNTs) with its exceptional thermal and mechanical properties hold the promise of delivering high performance nanocomposite materials. To utilize CNTs as effective reinforcement in metal nanocomposites, appropriate dispersion and robust interfacial adhesion between individual CNT and metal matrix have to be certain. This work presents a novel combined technique of nanoscale dispersion (NSD) of functionalized multiwalled carbon nanotubes (MWCNTs) in copper (Cu) matrix composite followed by powder injection molding (PIM). MWCNTs contents were varied from 0 to 10 volume fraction. Evidences on the existence of functional groups and microstructural analysis of the fabricated nanocomposites were determined using TEM, EDX, FESEM and FTIR. Thermal conductivity and elasticity measurements were also performed. The results showed that the impurities of the pristine MWCNTs such as Fe, Ni catalyst, and the amorphous carbon have been significantly removed after sonication process. FESEM and TEM observations showed high stability of MWCNTs at elevated temperatures and uniform dispersion of MWCNTs in Cu matrix at different volume fractions and sintering temperatures (950, 1000 and 1050 C). The experimentally measured thermal conductivities of Cu/MWCNTs nanocomposites showed remarkable increase (11.25% higher than pure sintered Cu) with addition of 1 vol.% MWCNTs, while the modulus of elasticity (Young's modulus) of Cu/MWCNTs nanocomposites sintered at 1050 C for 2 h was increased proportionally to the increment in MWCNTs contents.

Journal of Nanoengineering and Nanomanufacturing, 2013

Uniform dispersion of carbon nanotubes (CNTs) in metal composites has been by far the most signif... more Uniform dispersion of carbon nanotubes (CNTs) in metal composites has been by far the most significant challenge in the field of CNT-reinforced metal matrices. This work presents a new dispersion and fabrication technique of Carbon nanotubes (CNTs) reinforced copper (Cu) matrix nanocomposites. A combination of nanoscale dispersion of functionalized CNTs in low viscose media of dissolved paraffin wax under ultrasonication treatment followed by powder injection molding (PIM) technique was adopted. CNTs contents were varied from 0 to 10 vol.%. TEM, EDX, FESEM and Raman spectroscopy analysis were used for materials characterization. Information about the degree of purification and functionalization processes, evidences on the existence of the functional groups, effects of ultrasonication time on the treated CNTs, and microstructural analysis of the fabricated Cu/CNTs nanocomposites were determined. The results showed that the impurities of the pristine CNTs such as Fe, Ni catalyst and the amorphous carbon have been significantly removed after purification process. Meanwhile, FESEM and TEM observations showed high stability of CNTs at elevated temperatures. It also showed an excellent homogeneous dispersion of CNTs in Cu matrix and led to a strong interfacial bonding between Cu particles and individual CNTs.

MATEC Web of Conferences, 2014

Fiber orientation is a big challenge in short fiber reinforced composites. Powder injection moldi... more Fiber orientation is a big challenge in short fiber reinforced composites. Powder injection molding (PIM) process has some intrinsic fiber alignment associated with it. During PIM process fibers in skin region of moldings are aligned as these regions experience higher shear flow caused by the mold walls. Fibers in the core region remain randomly aligned as these regions are far from mold walls and experience lesser shear flow. In this study short carbon fiber (CF) reinforced copper matrix composite was developed by PIM process. Two copper composite feedstock formulations were prepared having 5 vol% and 10 vol% CFs and a wax based binder system. Fiber orientation was controlled during injection molding by using a modified mold that has a diverging sprue. The sprue creates converging flow when feedstock enters into the mold cavity. Fiber orientation was analysed after molding using FESEM. The orientation of fibers can be controlled by controlling flow of feedstock into the mold.

MATEC Web of Conferences, 2014

Intumescent fire retardant coating (IFRC) have been developed by using ammonium polyphosphate, ex... more Intumescent fire retardant coating (IFRC) have been developed by using ammonium polyphosphate, expandable graphite, melamine, boric acid, kaolin clay and alumina as fillers bound together with epoxy resin and cured with the help of curing agent. Five different formulations were developed with and without using fillers. Cured samples were burned in furnace at 500 o C for 2h for char expansion. Bunsen burner test was performed for 1h using UL-94 vertical burning test to investigate the thermal performance of IFRC. The resultant char obtained after burning of coated samples were characterized by using field emission scanning electron microscopy for char morphology. Char composition was analyzed by using fourier transform infrared spectroscopy. Thermogravimetric analysis was carried out to investigate the residual weight of coating. Results showed that formulation with 0.5 weight % of kaolin clay and 0.5 weight % of alumina provide best thermal performance, uniform and multi-porous char structure with high anti-oxidation property.

MATEC Web of Conferences, 2014

Composite have been widely used in industries which such as aircraft structural components, elect... more Composite have been widely used in industries which such as aircraft structural components, electric and electronics components, aerospace, and oil and gas fields due to their superior mechanical properties. Among machining process, drilling can be considered as one of the most important process in final machining of composite. In this research, vacuum assisted resin infusion method is use in fabricating the glass fiber reinforcement polymer samples, where different thickness of GFRP were used in the drilling process with different spindle speed. The results show that the temperature influences the damage factor of the drilling. Higher spindle speed will generate higher temperature that softens the matrix thus generating lower damage factor. The suitable drill bit temperature is between 150-200°C

MATEC Web of Conferences, 2014

The demand for mechanical fastening in composite materials is increasing due to their potential i... more The demand for mechanical fastening in composite materials is increasing due to their potential in large assemblies, aerospace and automotive industries. In practice, small components are integrated into large assemblies drilling holes in composite materials. Drilling defect free holes in composite presents many challenges during part assembly and services. This study presents the effects of cutting parameters used for drilling holes in glass fiber reinforced polymeric (GFRP) composites and hybrid fiber reinforced polymeric (HFRP) composites. Both the composites plates of 3 mm thickness were fabricated using a hand lay-up technique for the purpose of evaluating the effects of parameters on the quality of drilled holes. The holes were drilled using a 5 mm solid carbide twist drill at different spindle speed and feed rate. The quality of holes was assessed with respect to damage factor (F d) and surface roughness (Ra) of the drilled holes. Results showed that the HFRP composite experienced lower damage factor (F d) as compared to GFRP composite at lowerfeedrate or spindle speed. Scanning electron microscopic (SEM) examination revealed that the occurrence of delamination, fiber pull-out and matrix cracking was accelerated in the drilled holes at high spindle speed and feed rate.

Key Engineering Materials, 2013

Drilling generated heat is considered to have significant effect on the product. In this study, w... more Drilling generated heat is considered to have significant effect on the product. In this study, woven glass fiber reinforced epoxy composites were fabricated using Vacuum Resin Infusion technique. The composites were drilled using HSS twist drill bit at various drilling parameters. The temperature during drill was measured using infra red thermometer. The damage factor of drilled holes was measured using 3D non-contact surface measurement and correlates it with temperature. Results showed that low feed rate recorded maximum temperature and high fede rate showed lower heat generated during drilling. Damage factor measured at lower feed rate was high and low at high feed rate. This was considered due to evaporation of resin matrix.

This study was conducted to evaluate the effects of elemental boron on densification of 316L stai... more This study was conducted to evaluate the effects of elemental boron on densification of 316L stainless steels. Elemental nano size boron (nB) powder of 0.5, 1 and 1.5 wt. % was blended with 316L SS to produce homogeneous feedstock for low pressure powder injection molding (LPIM) process. LPIM molded samples were sintered at 12300C using high vacuum 10-5Torr. The Results showed that addition of elemental boron has favorable effects on densification. Addition of 0.5 wt% nano size elemental boron in 316L SS has enhanced densification up to 98.5%. Defect free gears were injection molded and sintered successfully using optimal sintering cycle.

MATEC Web of Conferences, 2014

Thermal conductivity of carbon nanotubes (CNTs) copper-matrix nanocomposites was predicted by usi... more Thermal conductivity of carbon nanotubes (CNTs) copper-matrix nanocomposites was predicted by using numerical approach. In the present study, twenty representative volume elements (RVEs) were modeled by assuming that the CNTs are distributed homogeneously in the copper (Cu) matrix. It is assumed that each RVE contains different pattern of CNTs distribution while the direction, diameter and length of CNTs are held constant. The effect of the CNTs-matrix interfacial resistance was also negligible. Therefore, it was observed that the predicted values of thermal conductivity would reach to the upper-bound rule of mixtures.

MATEC Web of Conferences, 2014

Due to the rapid growth of high performance electronics devices accompanied by overheating proble... more Due to the rapid growth of high performance electronics devices accompanied by overheating problem, heat dissipater nanocomposites material having ultra-high thermal conductivity and low coefficient of thermal expansion was proposed. In this work, a nanocomposite material made of copper (Cu) reinforced by multi-walled carbon nanotubes (CNTs) up to 10 vol. % was prepared and their thermal behaviour was measured experimentally and evaluated using numerical simulation. In order to numerically predict the thermal behaviour of Cu/CNTs composites, three different prediction methods were performed. The results showed that rules of mixture method records the highest thermal conductivity for all predicted composites. In contrast, the prediction model which takes into account the influence of the interface thermal resistance between CNTs and copper particles, has shown the lowest thermal conductivity which considered as the closest results to the experimental measurement. The experimentally measured thermal conductivities showed remarkable increase after adding 5 vol.% CNTs and higher than the thermal conductivities predicted via Nan models, indicating that the improved fabrication technique of powder injection molding that has been used to produced Cu/CNTs nanocomposites has overcome the challenges assumed in the mathematical models.

International Journal of Applied Physics and Mathematics, 2011

In this study, the flow behavior of multi-walled carbon nanotubes (CNTs) reinforced copper matrix... more In this study, the flow behavior of multi-walled carbon nanotubes (CNTs) reinforced copper matrix feedstocks is presented. The solid loadings in the copper feedstock were investigated in the ranges of 55-61 Vol. % using binder. Pure copper (Cu) and Cu/CNTs feedstocks were compounded using internal mixer machine for homogenous dispersion of solids in the binder. The flow behavior was measured using a capillary rheometer in the shear rate range expected to occur during powder injection molding. An acceptable increasing trend in viscosity of the copper feedstock with powder loading was recorded. Cu/CNTs composite feedstocks showed viscosity more than 1000 Pa.s which is most probably due to the addition of CNTs and increasing trend in viscosity of Cu/CNTs was noted as well. The results also identified that the feedstock containing 59 vol. % copper was most suitable for substitution of CNTs in Cu feedstock.

Applied Mechanics and Materials, 2013

Carbon nanotubes (CNTs) reinforced copper (Cu) matrix nanocomposites prepared via advanced fabric... more Carbon nanotubes (CNTs) reinforced copper (Cu) matrix nanocomposites prepared via advanced fabrication method is presented. Functionalization and ultrasonication processes have been applied to enhance the dispersion of purified CNTs and creates sidewalls groups that have the potential to bond CNTs to the metal matrix. The main part of this approach was metal injection molding (MIM) technique, which is a combination of powder metallurgy and plastic injection molding technique. Preparation of MIM feedstock required a melting and mixing process of binder system (polymers) with the solid loading, which has been carried out using a twin screw rotor machine. This machine provides a viscous media of the molten binder with high shear forces that allow the additives (carbon nanotubes/copper powder) to be mixed properly and exfoliate the CNTs clusters with uniformdispersion inside the Cu matrix. Subsequently, to prove our expected results, observation tests of TEM, SEM, FESEM and CNTS were em...

Procedia Engineering, 2016

Dolomite Clay was introduced in a traditional intumescent flame retardant system which contains a... more Dolomite Clay was introduced in a traditional intumescent flame retardant system which contains ammonium polyphosphate/expandable graphite/melamine (APP-EG-MEL) to evaluate its effects on char morphology and fire performance. The effect of dolomite clay on the fireresistance and thermal properties of expandable graphite based Intumescent fire retardant coatings has been investigated by using Bunsen burner fire test and thermal gravimetric (TG) techniques. The current study describes the effects of Dolomite Clay on the heat shielding performance of intumescent passive fireproofing coatings during fire testing. The fire performance of dolomite clay reinforced intumescent coating formulations were evaluated by Bunsen burner fire test according to ASTM E-119. Results showed that the dolomite reinforcement in IFRC formulation significantly reduced the steel substrate temperature up to 180 °C after 1 hour of fire exposure. The coating degradation was studied using thermogravimetric analysis (TGA). The physical morphology and alignment of intumescent char residue were studied by field emission scanning electron microscopy (FESEM). TGA analysis revealed that IFD (8) containing 8 wt. % of dolomite clay enhanced residual weight by 37.30%. It is suggested that Dolomite clay can enhance the fire performance and can significantly affect the formation of dense and continuous char if incorporated as a filler in conventional intumescent fire resistive systems.

Metal Powder Report

Ni-Mo-TiC samples were prepared from powder and vacuum hot pressed. The specimens were heated to ... more Ni-Mo-TiC samples were prepared from powder and vacuum hot pressed. The specimens were heated to melting in microgravity conditions. The structures are shown to consist of globular TiC particles in a Ni-Mo matrix and the distributions of elements were determined by Auger spectroscopy. It is suggested that thermal convection and gravity segregation were absent as a result of microgravity processing.

Progress in Organic Coatings

International Journal of Powder Metallurgy, 2008

Applied Mechanics and Materials, Jul 16, 2014

Drill point angle of twist drill has a significant effect on thrust force and delamination factor... more Drill point angle of twist drill has a significant effect on thrust force and delamination factor on drilled holes in fiber reinforced polymer (FRP) composites. In this study, three drill point angle of twist drill; 85°, 118° and 135° were used to drill holes in hybrid fiber reinforced polymeric composite (HFRP). HFRP composites were fabricated using vacuum infusion molding (VIM) technique. The test samples were cured at 90°C for two hours. In drilling process various drill point angle and feed rate were employed to investigate the effect of both parameters on thrust force and delamination factor when drilling the HFRP composite. The results showed that small drill point angle and low feed rate can reduce the thrust force leading to the reduction of damage factor at the hole's entrance and exit.

International Journal of Powder Metallurgy, 2006

Résumé/Abstract Optimum machine molding parameters were identified and defect-free moldings of Si... more Résumé/Abstract Optimum machine molding parameters were identified and defect-free moldings of SiC-reinforced aluminum alloy matrix composites (AMCs) were produced by powder injection molding (PIM). Fiber orientation was characterized qualitatively. Highly ...

MATEC Web of Conferences, 2014

Various types of intumescent fire retardant coatings (IFRC's) have been used to protect the subst... more Various types of intumescent fire retardant coatings (IFRC's) have been used to protect the substrates exposed to fire. In current study, high temperature filler Wollastonite (W) filler was used to improve fire performance of intumescent fire retardant coating. The basic ingredients of the coating were ammonium poly-phosphate (APP) as acid source, expandable graphite (EG) as carbon source, melamine (MEL) as blowing agent in epoxy binder, boric acid as additive and hardener as curing agent. In this study a range of coating formulations were developed by using different weight percentages of Wollastonite filler. The coated steel substrate samples were tested for fire performance using Bunsen burner and char expansion was measured using furnace fire test. Composition of the char was determined by X-ray diffraction (XRD) technique. The char morphology was studied using field emission scanning electron microscopy (FESEM). Results showed that Intumescent coating with addition of Wollastonite filler enhanced anti-oxidation of the char. Presence of phosphorus, calcium and silicon in char layer further improved the thermal stability of char. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net.

Nanoscience and Nanotechnology Letters, 2014

Carbon nanotubes (CNTs) with its exceptional thermal and mechanical properties hold the promise o... more Carbon nanotubes (CNTs) with its exceptional thermal and mechanical properties hold the promise of delivering high performance nanocomposite materials. To utilize CNTs as effective reinforcement in metal nanocomposites, appropriate dispersion and robust interfacial adhesion between individual CNT and metal matrix have to be certain. This work presents a novel combined technique of nanoscale dispersion (NSD) of functionalized multiwalled carbon nanotubes (MWCNTs) in copper (Cu) matrix composite followed by powder injection molding (PIM). MWCNTs contents were varied from 0 to 10 volume fraction. Evidences on the existence of functional groups and microstructural analysis of the fabricated nanocomposites were determined using TEM, EDX, FESEM and FTIR. Thermal conductivity and elasticity measurements were also performed. The results showed that the impurities of the pristine MWCNTs such as Fe, Ni catalyst, and the amorphous carbon have been significantly removed after sonication process. FESEM and TEM observations showed high stability of MWCNTs at elevated temperatures and uniform dispersion of MWCNTs in Cu matrix at different volume fractions and sintering temperatures (950, 1000 and 1050 C). The experimentally measured thermal conductivities of Cu/MWCNTs nanocomposites showed remarkable increase (11.25% higher than pure sintered Cu) with addition of 1 vol.% MWCNTs, while the modulus of elasticity (Young's modulus) of Cu/MWCNTs nanocomposites sintered at 1050 C for 2 h was increased proportionally to the increment in MWCNTs contents.

Journal of Nanoengineering and Nanomanufacturing, 2013

Uniform dispersion of carbon nanotubes (CNTs) in metal composites has been by far the most signif... more Uniform dispersion of carbon nanotubes (CNTs) in metal composites has been by far the most significant challenge in the field of CNT-reinforced metal matrices. This work presents a new dispersion and fabrication technique of Carbon nanotubes (CNTs) reinforced copper (Cu) matrix nanocomposites. A combination of nanoscale dispersion of functionalized CNTs in low viscose media of dissolved paraffin wax under ultrasonication treatment followed by powder injection molding (PIM) technique was adopted. CNTs contents were varied from 0 to 10 vol.%. TEM, EDX, FESEM and Raman spectroscopy analysis were used for materials characterization. Information about the degree of purification and functionalization processes, evidences on the existence of the functional groups, effects of ultrasonication time on the treated CNTs, and microstructural analysis of the fabricated Cu/CNTs nanocomposites were determined. The results showed that the impurities of the pristine CNTs such as Fe, Ni catalyst and the amorphous carbon have been significantly removed after purification process. Meanwhile, FESEM and TEM observations showed high stability of CNTs at elevated temperatures. It also showed an excellent homogeneous dispersion of CNTs in Cu matrix and led to a strong interfacial bonding between Cu particles and individual CNTs.

MATEC Web of Conferences, 2014

Fiber orientation is a big challenge in short fiber reinforced composites. Powder injection moldi... more Fiber orientation is a big challenge in short fiber reinforced composites. Powder injection molding (PIM) process has some intrinsic fiber alignment associated with it. During PIM process fibers in skin region of moldings are aligned as these regions experience higher shear flow caused by the mold walls. Fibers in the core region remain randomly aligned as these regions are far from mold walls and experience lesser shear flow. In this study short carbon fiber (CF) reinforced copper matrix composite was developed by PIM process. Two copper composite feedstock formulations were prepared having 5 vol% and 10 vol% CFs and a wax based binder system. Fiber orientation was controlled during injection molding by using a modified mold that has a diverging sprue. The sprue creates converging flow when feedstock enters into the mold cavity. Fiber orientation was analysed after molding using FESEM. The orientation of fibers can be controlled by controlling flow of feedstock into the mold.

MATEC Web of Conferences, 2014

Intumescent fire retardant coating (IFRC) have been developed by using ammonium polyphosphate, ex... more Intumescent fire retardant coating (IFRC) have been developed by using ammonium polyphosphate, expandable graphite, melamine, boric acid, kaolin clay and alumina as fillers bound together with epoxy resin and cured with the help of curing agent. Five different formulations were developed with and without using fillers. Cured samples were burned in furnace at 500 o C for 2h for char expansion. Bunsen burner test was performed for 1h using UL-94 vertical burning test to investigate the thermal performance of IFRC. The resultant char obtained after burning of coated samples were characterized by using field emission scanning electron microscopy for char morphology. Char composition was analyzed by using fourier transform infrared spectroscopy. Thermogravimetric analysis was carried out to investigate the residual weight of coating. Results showed that formulation with 0.5 weight % of kaolin clay and 0.5 weight % of alumina provide best thermal performance, uniform and multi-porous char structure with high anti-oxidation property.

MATEC Web of Conferences, 2014

Composite have been widely used in industries which such as aircraft structural components, elect... more Composite have been widely used in industries which such as aircraft structural components, electric and electronics components, aerospace, and oil and gas fields due to their superior mechanical properties. Among machining process, drilling can be considered as one of the most important process in final machining of composite. In this research, vacuum assisted resin infusion method is use in fabricating the glass fiber reinforcement polymer samples, where different thickness of GFRP were used in the drilling process with different spindle speed. The results show that the temperature influences the damage factor of the drilling. Higher spindle speed will generate higher temperature that softens the matrix thus generating lower damage factor. The suitable drill bit temperature is between 150-200°C

MATEC Web of Conferences, 2014

The demand for mechanical fastening in composite materials is increasing due to their potential i... more The demand for mechanical fastening in composite materials is increasing due to their potential in large assemblies, aerospace and automotive industries. In practice, small components are integrated into large assemblies drilling holes in composite materials. Drilling defect free holes in composite presents many challenges during part assembly and services. This study presents the effects of cutting parameters used for drilling holes in glass fiber reinforced polymeric (GFRP) composites and hybrid fiber reinforced polymeric (HFRP) composites. Both the composites plates of 3 mm thickness were fabricated using a hand lay-up technique for the purpose of evaluating the effects of parameters on the quality of drilled holes. The holes were drilled using a 5 mm solid carbide twist drill at different spindle speed and feed rate. The quality of holes was assessed with respect to damage factor (F d) and surface roughness (Ra) of the drilled holes. Results showed that the HFRP composite experienced lower damage factor (F d) as compared to GFRP composite at lowerfeedrate or spindle speed. Scanning electron microscopic (SEM) examination revealed that the occurrence of delamination, fiber pull-out and matrix cracking was accelerated in the drilled holes at high spindle speed and feed rate.

Key Engineering Materials, 2013

Drilling generated heat is considered to have significant effect on the product. In this study, w... more Drilling generated heat is considered to have significant effect on the product. In this study, woven glass fiber reinforced epoxy composites were fabricated using Vacuum Resin Infusion technique. The composites were drilled using HSS twist drill bit at various drilling parameters. The temperature during drill was measured using infra red thermometer. The damage factor of drilled holes was measured using 3D non-contact surface measurement and correlates it with temperature. Results showed that low feed rate recorded maximum temperature and high fede rate showed lower heat generated during drilling. Damage factor measured at lower feed rate was high and low at high feed rate. This was considered due to evaporation of resin matrix.