Prof. Abdel-Nasser Omran | Al-Azhar University (original) (raw)
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Papers by Prof. Abdel-Nasser Omran
Science of advanced materials, 2018
A Ti-30Nb-4Sn weight percentage alloy was fabricated using a powder metallurgy technique consisti... more A Ti-30Nb-4Sn weight percentage alloy was fabricated using a powder metallurgy technique consisting of high energy ball milling and consolidation at various temperatures. The initial powdered materials were mixed and milled for 3 and 6 hr. The powders were then compacted and sintered at a temperature of 900-1000 C. It was observed that the titanium was transformed from to phase after 6 hr of milling, and the sample sintered at 1000 C contained trace amounts of titanium. The Vicker's hardness increases as the milling time and sintering temperature increase, the hardness values range from 354 to 386 HV. The hardness contour map using nanoindentation tester indicated that the spatial variation of the hardness values is appeared and the background hardness increases with increasing the milling time in the sintered alloys. The Young's modulus was nearly constant for all sintered Ti-30Nb-4Sn samples at each milling time. The Young's modulus was low (63.93 to 66.4 GPa) compared to the standard alloy, Ti-6Al-4V (103.34 GPa). These samples show enhanced resistance to wear with increased milling times. Additionally, the Ti-30Nb-4Sn alloys have better corrosion properties than the Ti-6Al-4V alloy. All of the samples described herein have improved biocompatibility compared to the standard Ti-6Al-4V alloy ingot, with a decrease in biocompatibility observed at longer milling times.
Al-TiC master alloys have been widely investigated for many years as grain refiner for aluminium ... more Al-TiC master alloys have been widely investigated for many years as grain refiner for aluminium and its alloys. In this work, the Al-TiC master alloys are synthesized using powder metallurgy technique through the mixing of aluminium and TiC powders with different TiC contents 3.75 (3), 5(4), 6.25(5) and 7.5(6) Wt% TiC(Wt% Ti). The mixing powders with different contents of TiC were pressed in cylinder shape. The pressed specimens were sintered from 450 o C in a tube furnace under argon atmosphere for 2 hrs. The produced alloys before and after sintering are examined using SEM, EDX and XRD. The results indicate that, the Al-TiC alloy containing fine TiC particles dispersed in all matrix was successfully prepared. The prepared Al-TiC alloys with different contents of TiC were evaluated using the KBI test mold as grain refiner for pure aluminum and its alloys. The results indicate that the prepared Al-TiC master alloy is high grain refining efficiency for pure aluminum and its alloys.
Al-TiC master alloys have been widely investigated for many years as grain refiner for aluminium ... more Al-TiC master alloys have been widely investigated for many years as grain refiner for aluminium and its alloys. In this work, the Al-TiC master alloys are synthesized using powder metallurgy technique through the mixing of aluminium and TiC powders with different TiC contents 3.75 (3), 5(4), 6.25(5) and 7.5(6) Wt% TiC(Wt% Ti). The mixing powders with different contents of TiC were pressed in cylinder shape. The pressed specimens were sintered from 450 o C in a tube furnace under argon atmosphere for 2 hrs. The produced alloys before and after sintering are examined using SEM, EDX and XRD. The results indicate that, the Al-TiC alloy containing fine TiC particles dispersed in all matrix was successfully prepared. The prepared Al-TiC alloys with different contents of TiC were evaluated using the KBI test mold as grain refiner for pure aluminum and its alloys. The results indicate that the prepared Al-TiC master alloy is high grain refining efficiency for pure aluminum and its alloys.
EVWUDFW Al-Ti-C master alloys have been widely investigated for many years as grain refiner for a... more EVWUDFW Al-Ti-C master alloys have been widely investigated for many years as grain refiner for aluminium and its alloys. In this work, the Al-Ti-C master alloys are synthesized using powder metallurgy technique through the mixing of aluminium and TiC powders with different TiC contents 3.75 (3), 5(4), 6.25(5) and 7.5(6) Wt% TiC(Wt% Ti). The mixing powders with different contents of TiC were pressed in cylinder shape. The pressed specimens were sintered from 450 o C in a tube furnace under argon atmosphere for 2 hrs. The produced alloys before and after sintering are examined using SEM, EDX and XRD. The results indicate that, the Al-TiC alloy containing fine TiC particles dispersed in all matrix was successfully prepared. The prepared Al-TiC alloys with different contents of TiC were evaluated using the KBI test mold as grain refiner for pure aluminum and its alloys. The results indicate that the prepared Al-TiC master alloy is high grain refining efficiency for pure aluminum and its alloys.
Al-V insitu composite reinforced by submicron size Al 3 V intermetallic compound has been obtaine... more Al-V insitu composite reinforced by submicron size Al 3 V intermetallic compound has been obtained using new technique. The insitu Al 3 V intermetallic compound was homogeneously embedded in the Al matrix. It is produced by mixing vanadium pentoxide with powdered aluminium for 6 hr in a cylindrical polyethylene bottle using a ZrO 2 ball. The mixture was added to molten aluminium at different temperature and different Al powdered/V 2 O 5 Wt. ratio. The produced composites were examined using XRD, SEM, EDS, DTA, light microscopy and hardness testing. The results indicated that, firstly the powder aluminium reduced the V 2 O 5 to librate vanadium ions, the later reacted with molten aluminium to form the required composite. The recovery of vanadium in the prepared composite is reached up to 8% and the maximium efficiency of the V recovery up to 80% has been achieved. Also, it has proved certainly by introducing many evidence using XRD, SEM, EDS, DTA and X ray mapping that, this compound is Al 3 V intermetallic compound. According to DTA analysis, the reduction reaction is exthothermic reaction at temperature more than 600 o C and the bath temperature uncontrolled reached up to 1000 o C. The presence of Al 3 V compound in the aluminium matrix enhanced and improved the hardness of the prepared composite.
This paper investigates on methods for producing ductile cast iron (SGI). The processing paramete... more This paper investigates on methods for producing ductile cast iron (SGI). The processing parameters affecting the production of SGI were studied. These parameters include chemical composition, thickness of the castings, mechanical properties, alloying elements and microstructures. The results indicated that, the nodularity is increased with increasing the percentage of Mg contents, moreover the nodularity decreased with increasing thickness of the castings. The amount of pearlite is increased sharply with increasing Cu and Mn contents in the produced SGI. The tensile strength hardness and wear are increased by increasing Mg contents and nodularity. Empirical equations were correlated to indicate the relations among nodularity, Mg contents, pearlite and other parameters.
In the present paper friction stir-induced diffusion bonding is used for joining sheets of 5754 a... more In the present paper friction stir-induced diffusion bonding is used for joining sheets of 5754 aluminum alloy to coated high strength steels (DP600 and 22MnB5) by promoting diffusion bonding in an overlap configuration. Mechanical performance and microstructures of joints were analyzed by overlap shear testing, metallography, and X-ray diffraction. Our results show that the strength of joint is dependent upon tool travel speed and the depth of the tool pin relative to the steel surface. The thickness and types of intermetallic compounds formed at the interface play a significant role in achieving a joint with optimum performance. That is, the formation of high aluminum composition intermetallic compounds (i.e. Al 5 Fe 2 ) at the interface of the friction stir lap joint appeared to have a more negative effect on joint strength compared to the presence of high iron composition intermetallic phases (i.e. FeAl). This is in agreement with previously reported findings that FeAl intermetallic can improve the fracture toughness and interface strength in Al/St joints.
Journal of Materials Science, 2008
In the present study colloidal-gel electrospinning technique is proposed to produce new shape of ... more In the present study colloidal-gel electrospinning technique is proposed to produce new shape of nickel oxide hollow nanoparticles. In the colloidal-gel process, a colloidal precursor was prepared by dissolving nickel acetate tetra hydrate in ethanol at 352 K. The precursor was mixed with poly(vinyl acetate)/N, N-dimethylformamide (14 wt%). The polymer-precursor mixture was electrospun at relatively low voltage depending on the concentration of nickel acetate in the precursor. The obtained mat was dried under vacuum at 353 K for 24 h, and then sintered at 827 K for 3 h. The XRD and SEM results indicated that the proposed methodology produces pure nickel oxide hollow nanoparticles with beads-like form.
The anode spike problem faces the operating staff in field of the aluminum reduction cells from t... more The anode spike problem faces the operating staff in field of the aluminum reduction cells from time to time. This paper presents the reasons of increasing the anode spikes and the procedures for solving this problem. The effect of anode spikes on the pot line performance was studied before and during spike formation. The pot line operating parameters were changed as follows: the current efficiency changed from 95.13 to 93.3%, energy consumption from 13873 k to 14123 k w hr /ton Al and net carbon consumption from 407 to 440 kg/ton Al. The anode spikes frequency has increased sharply from 0.1 to about 2 spike/ cell/ month. Also the anode carries current more than 1.3 multiple in the average voltage drop in all the cell anodes was considered as spiky anode. The maximum carbon content in the frozen bath layer formed underside the anode reaches to 9.6 %. Moreover the behavior of frozen bath layer formed underside the anode blocks was studied at different times from putting the new anodes into the cells.
The effect of reaction time on the formation of Al 3 Ti and TiC during preparation of the Al-Ti-C... more The effect of reaction time on the formation of Al 3 Ti and TiC during preparation of the Al-Ti-C master alloys was investigated using the reaction between mixture of potassium fluotitanate (K 2 TiF 6 ) and graphite with molten aluminium, The produced alloys were tested using XRD, SEM and EDS. These tests and thermodynamics data, shown that the Al 3 Ti was obtained as soon as the mixture has been added. Al 3 Ti was formed by vigorous reaction, thereafter, the TiC was formed around the Al3Ti. The TiC contents were measured using XRD, it was found that the amount of TiC increases with increasing reaction Time. Moreover, the TiC is increased with increasing Ti contents in the produced alloys. The produced alloys were tested as grain refiner for pure aluminium, and illustrated that, these alloys have given a good performance with increasing reaction time as grain refining efficiency of pure aluminium and its alloys.
Science of advanced materials, 2018
A Ti-30Nb-4Sn weight percentage alloy was fabricated using a powder metallurgy technique consisti... more A Ti-30Nb-4Sn weight percentage alloy was fabricated using a powder metallurgy technique consisting of high energy ball milling and consolidation at various temperatures. The initial powdered materials were mixed and milled for 3 and 6 hr. The powders were then compacted and sintered at a temperature of 900-1000 C. It was observed that the titanium was transformed from to phase after 6 hr of milling, and the sample sintered at 1000 C contained trace amounts of titanium. The Vicker's hardness increases as the milling time and sintering temperature increase, the hardness values range from 354 to 386 HV. The hardness contour map using nanoindentation tester indicated that the spatial variation of the hardness values is appeared and the background hardness increases with increasing the milling time in the sintered alloys. The Young's modulus was nearly constant for all sintered Ti-30Nb-4Sn samples at each milling time. The Young's modulus was low (63.93 to 66.4 GPa) compared to the standard alloy, Ti-6Al-4V (103.34 GPa). These samples show enhanced resistance to wear with increased milling times. Additionally, the Ti-30Nb-4Sn alloys have better corrosion properties than the Ti-6Al-4V alloy. All of the samples described herein have improved biocompatibility compared to the standard Ti-6Al-4V alloy ingot, with a decrease in biocompatibility observed at longer milling times.
Al-TiC master alloys have been widely investigated for many years as grain refiner for aluminium ... more Al-TiC master alloys have been widely investigated for many years as grain refiner for aluminium and its alloys. In this work, the Al-TiC master alloys are synthesized using powder metallurgy technique through the mixing of aluminium and TiC powders with different TiC contents 3.75 (3), 5(4), 6.25(5) and 7.5(6) Wt% TiC(Wt% Ti). The mixing powders with different contents of TiC were pressed in cylinder shape. The pressed specimens were sintered from 450 o C in a tube furnace under argon atmosphere for 2 hrs. The produced alloys before and after sintering are examined using SEM, EDX and XRD. The results indicate that, the Al-TiC alloy containing fine TiC particles dispersed in all matrix was successfully prepared. The prepared Al-TiC alloys with different contents of TiC were evaluated using the KBI test mold as grain refiner for pure aluminum and its alloys. The results indicate that the prepared Al-TiC master alloy is high grain refining efficiency for pure aluminum and its alloys.
Al-TiC master alloys have been widely investigated for many years as grain refiner for aluminium ... more Al-TiC master alloys have been widely investigated for many years as grain refiner for aluminium and its alloys. In this work, the Al-TiC master alloys are synthesized using powder metallurgy technique through the mixing of aluminium and TiC powders with different TiC contents 3.75 (3), 5(4), 6.25(5) and 7.5(6) Wt% TiC(Wt% Ti). The mixing powders with different contents of TiC were pressed in cylinder shape. The pressed specimens were sintered from 450 o C in a tube furnace under argon atmosphere for 2 hrs. The produced alloys before and after sintering are examined using SEM, EDX and XRD. The results indicate that, the Al-TiC alloy containing fine TiC particles dispersed in all matrix was successfully prepared. The prepared Al-TiC alloys with different contents of TiC were evaluated using the KBI test mold as grain refiner for pure aluminum and its alloys. The results indicate that the prepared Al-TiC master alloy is high grain refining efficiency for pure aluminum and its alloys.
EVWUDFW Al-Ti-C master alloys have been widely investigated for many years as grain refiner for a... more EVWUDFW Al-Ti-C master alloys have been widely investigated for many years as grain refiner for aluminium and its alloys. In this work, the Al-Ti-C master alloys are synthesized using powder metallurgy technique through the mixing of aluminium and TiC powders with different TiC contents 3.75 (3), 5(4), 6.25(5) and 7.5(6) Wt% TiC(Wt% Ti). The mixing powders with different contents of TiC were pressed in cylinder shape. The pressed specimens were sintered from 450 o C in a tube furnace under argon atmosphere for 2 hrs. The produced alloys before and after sintering are examined using SEM, EDX and XRD. The results indicate that, the Al-TiC alloy containing fine TiC particles dispersed in all matrix was successfully prepared. The prepared Al-TiC alloys with different contents of TiC were evaluated using the KBI test mold as grain refiner for pure aluminum and its alloys. The results indicate that the prepared Al-TiC master alloy is high grain refining efficiency for pure aluminum and its alloys.
Al-V insitu composite reinforced by submicron size Al 3 V intermetallic compound has been obtaine... more Al-V insitu composite reinforced by submicron size Al 3 V intermetallic compound has been obtained using new technique. The insitu Al 3 V intermetallic compound was homogeneously embedded in the Al matrix. It is produced by mixing vanadium pentoxide with powdered aluminium for 6 hr in a cylindrical polyethylene bottle using a ZrO 2 ball. The mixture was added to molten aluminium at different temperature and different Al powdered/V 2 O 5 Wt. ratio. The produced composites were examined using XRD, SEM, EDS, DTA, light microscopy and hardness testing. The results indicated that, firstly the powder aluminium reduced the V 2 O 5 to librate vanadium ions, the later reacted with molten aluminium to form the required composite. The recovery of vanadium in the prepared composite is reached up to 8% and the maximium efficiency of the V recovery up to 80% has been achieved. Also, it has proved certainly by introducing many evidence using XRD, SEM, EDS, DTA and X ray mapping that, this compound is Al 3 V intermetallic compound. According to DTA analysis, the reduction reaction is exthothermic reaction at temperature more than 600 o C and the bath temperature uncontrolled reached up to 1000 o C. The presence of Al 3 V compound in the aluminium matrix enhanced and improved the hardness of the prepared composite.
This paper investigates on methods for producing ductile cast iron (SGI). The processing paramete... more This paper investigates on methods for producing ductile cast iron (SGI). The processing parameters affecting the production of SGI were studied. These parameters include chemical composition, thickness of the castings, mechanical properties, alloying elements and microstructures. The results indicated that, the nodularity is increased with increasing the percentage of Mg contents, moreover the nodularity decreased with increasing thickness of the castings. The amount of pearlite is increased sharply with increasing Cu and Mn contents in the produced SGI. The tensile strength hardness and wear are increased by increasing Mg contents and nodularity. Empirical equations were correlated to indicate the relations among nodularity, Mg contents, pearlite and other parameters.
In the present paper friction stir-induced diffusion bonding is used for joining sheets of 5754 a... more In the present paper friction stir-induced diffusion bonding is used for joining sheets of 5754 aluminum alloy to coated high strength steels (DP600 and 22MnB5) by promoting diffusion bonding in an overlap configuration. Mechanical performance and microstructures of joints were analyzed by overlap shear testing, metallography, and X-ray diffraction. Our results show that the strength of joint is dependent upon tool travel speed and the depth of the tool pin relative to the steel surface. The thickness and types of intermetallic compounds formed at the interface play a significant role in achieving a joint with optimum performance. That is, the formation of high aluminum composition intermetallic compounds (i.e. Al 5 Fe 2 ) at the interface of the friction stir lap joint appeared to have a more negative effect on joint strength compared to the presence of high iron composition intermetallic phases (i.e. FeAl). This is in agreement with previously reported findings that FeAl intermetallic can improve the fracture toughness and interface strength in Al/St joints.
Journal of Materials Science, 2008
In the present study colloidal-gel electrospinning technique is proposed to produce new shape of ... more In the present study colloidal-gel electrospinning technique is proposed to produce new shape of nickel oxide hollow nanoparticles. In the colloidal-gel process, a colloidal precursor was prepared by dissolving nickel acetate tetra hydrate in ethanol at 352 K. The precursor was mixed with poly(vinyl acetate)/N, N-dimethylformamide (14 wt%). The polymer-precursor mixture was electrospun at relatively low voltage depending on the concentration of nickel acetate in the precursor. The obtained mat was dried under vacuum at 353 K for 24 h, and then sintered at 827 K for 3 h. The XRD and SEM results indicated that the proposed methodology produces pure nickel oxide hollow nanoparticles with beads-like form.
The anode spike problem faces the operating staff in field of the aluminum reduction cells from t... more The anode spike problem faces the operating staff in field of the aluminum reduction cells from time to time. This paper presents the reasons of increasing the anode spikes and the procedures for solving this problem. The effect of anode spikes on the pot line performance was studied before and during spike formation. The pot line operating parameters were changed as follows: the current efficiency changed from 95.13 to 93.3%, energy consumption from 13873 k to 14123 k w hr /ton Al and net carbon consumption from 407 to 440 kg/ton Al. The anode spikes frequency has increased sharply from 0.1 to about 2 spike/ cell/ month. Also the anode carries current more than 1.3 multiple in the average voltage drop in all the cell anodes was considered as spiky anode. The maximum carbon content in the frozen bath layer formed underside the anode reaches to 9.6 %. Moreover the behavior of frozen bath layer formed underside the anode blocks was studied at different times from putting the new anodes into the cells.
The effect of reaction time on the formation of Al 3 Ti and TiC during preparation of the Al-Ti-C... more The effect of reaction time on the formation of Al 3 Ti and TiC during preparation of the Al-Ti-C master alloys was investigated using the reaction between mixture of potassium fluotitanate (K 2 TiF 6 ) and graphite with molten aluminium, The produced alloys were tested using XRD, SEM and EDS. These tests and thermodynamics data, shown that the Al 3 Ti was obtained as soon as the mixture has been added. Al 3 Ti was formed by vigorous reaction, thereafter, the TiC was formed around the Al3Ti. The TiC contents were measured using XRD, it was found that the amount of TiC increases with increasing reaction Time. Moreover, the TiC is increased with increasing Ti contents in the produced alloys. The produced alloys were tested as grain refiner for pure aluminium, and illustrated that, these alloys have given a good performance with increasing reaction time as grain refining efficiency of pure aluminium and its alloys.
8 th Pacific Rim International Congress on Advanced Materials and Processing, 2013
Journal of Alloys and Compounds, 2009
Compacted graphite cast iron (CGI) has many high temperature applications on account of its super... more Compacted graphite cast iron (CGI) has many high temperature applications on account of its superior thermal properties. This study has examined the behavior of compacted graphite cast iron at elevated temperatures to help facilitate its increased use in high temperature applications. Mechanical, wear and heat exposure tests were carried out. The tensile strength at elevated temperature was found to increase linearly with increasing nodularity % and pearlite %. In addition, the tensile strength was found to decrease with increasing temperature at the same nodularity % and pearlite % and the wear loss was found to decrease slightly with increasing nodularity % and pearlite %. At the same nodularity % and pearlite %, the wear increased with increasing temperature from room temperature. On the other hand, under an Ar atmosphere, the amount of wear loss decreased slightly at the same temperature, nodularity % and pearlite %. The losses due to heat exposure increased with increasing nodularity % and pearlite % at all temperatures, and the heat exposure losses increased with increasing temperature at the same nodularity % and pearlite %.
Journal of Materials Processing Technology, 2009
Subcritical water Alkaline hydrolysis Thermal elimination a b s t r a c t
Materials Science and Engineering: C, 2008
In the present study, subcritical water and alkaline hydrolysis methods are proposed methodologie... more In the present study, subcritical water and alkaline hydrolysis methods are proposed methodologies for extraction of natural hydroxyapatite bioceramic from bovine bone. In these processes, the bovine bones powder were treated by high pressure water at 250 °C for 1 h and 25% (wt) ...
Metallurgical and Materials Transactions A, 2012
ABSTRACT A developed Ti-35 pct Nb-2.5 pct Sn (wt pct) alloy was synthesized by mechanical alloyin... more ABSTRACT A developed Ti-35 pct Nb-2.5 pct Sn (wt pct) alloy was synthesized by mechanical alloying using high-energy ball-milled powders, and the powder consolidation was done by pulsed current activated sintering (PCAS). The starting powder materials were mixed for 24 hours and then milled by high-energy ball milling (HEBM) for 1, 4, and 12 hours. The bulk solid samples were fabricated by PCAS at 1073 K to 1373 K (800 °C to 1100 °C) for a short time, followed by rapid cooling to 773 K (500 °C). The relative density of the sintered samples was about 93 pct. The Ti was completely transformed from α to β-Ti phase after milling for 12 hours in powder state, and the specimen sintered at 1546 K (1273 °C) was almost transformed to β-Ti phase. The homogeneity of the sintered specimen increased with increasing milling time and sintering temperature, as did its hardness, reaching 400 HV after 12 hours of milling. The Young’s modulus was almost constant for all sintered Ti-35 pct Nb-2.5 pct Sn specimens at different milling times. The Young’s modulus was low (63.55 to 65.3 GPa) compared to that of the standard alloy of Ti-6Al-4V (100 GPa). The wear resistance of the sintered specimen increased with increasing milling time. The 12-hour milled powder exhibited the best wear resistance.
Metallurgical and Materials Transactions A, 2011
Al-Ti-C master alloys have a great potential as efficient grain refiners for aluminum and its all... more Al-Ti-C master alloys have a great potential as efficient grain refiners for aluminum and its alloys. In the present work, the Al-Ti-C master alloys are synthesized via a relatively novel technique through the reaction of a compacted mixture of K 2 TiF 6 and graphite with molten aluminum. The obtained alloys are examined using scanning electron microscopy (SEM), energy-dispersive spectroscopy, and X-ray diffraction (XRD) methods. The results indicate that the produced Al-Ti-C master alloys contain TiC and TiAl 3 particles within the aluminum matrix. Also, these alloys were evaluated using the KBI test mold. The results indicate that the produced Al-Ti-C master alloy is an efficient grain refiner for pure aluminum and its alloys compared with the Al-Ti-B one. The factors affecting the grain refinement of aluminum and its alloys are studied. The proper conditions for evaluating the efficiency of the produced Al-Ti-C master alloy to obtain a minimum grain size are as follows: temperature, 993 K (720°C); holding time, 2 minutes; and (Ti/Al) weight ratio, 0.01 pct.
Metals and Materials International, 2008
This study was conducted to observe the phase transformation of Ti-35 %Nb-2.5 %Sn during milling ... more This study was conducted to observe the phase transformation of Ti-35 %Nb-2.5 %Sn during milling for various milling times using a mixing machine and a high-energy ball milling machine (HEBM). In this work, niobium was chosen as the β stabilizer and tin as the reducer of the elastic modulus. The starting materials were blended and milled in a mixing machine (24 h) and a high-energy ball mill machine (1 h, 4 h, and 12 h). The particle sizes and phases of the produced powders were analyzed using XRD, SEM, TEM, and PSD; the titanium was found to be fully transformed from the α phase to Ti the β phase Ti after 12 h of milling.
Science of Advanced Materials, 2009
ABSTRACT A novel -Ti-35%Nb-2.5%Sn (wt%) alloy was synthesized by mechanical alloying of high ene... more ABSTRACT A novel -Ti-35%Nb-2.5%Sn (wt%) alloy was synthesized by mechanical alloying of high energy ball milled powders and rapid powder consolidation with pulsed current activated sintering (PCAS). The starting powder materials were 24 hr mixed powders and powders were produced by high energy ball milling for 1 hr, 4 hr and 12 hr respectively. The bulk solid samples were fabricated by the PCAS at temperature of 800–1100 °C for a short time, followed by rapid cooling to 500 °C. The relative density of the sintered samples was about 93%. It was found that the Ti was completely transformed from α to phase after milling for 12 hr in powder state, and the sintered specimen at 1000 °C was almost -Ti phase. The homogeneity of the sintered specimen increased with increasing milling time and sintering temperature. All sintered specimens were more biocompatible compared to the standard Ti-6Al-4V alloy, and the biocompatibility decreased with increasing milling time. The -Ti-35%Nb-2.5%Sn specimen synthesized by PCAS using high energy ball milled (HEBM) powder had better biocompatibility than Ti-6Al-4V alloy. Also, mixed and milled Ti-35%Nb-2.5%Sn specimens had better corrosion property than Ti-6Al-4V alloy.
Korean Journal of Metals and Materials, 2010
Materials & Design, 2014
Please cite this article as: Haghshenas, M., Abdel-Gwad, A., Omran, A.M., Gökçe, B., Sahraeinejad... more Please cite this article as: Haghshenas, M., Abdel-Gwad, A., Omran, A.M., Gökçe, B., Sahraeinejad, S., Gerlich, A.P., Friction stir weld assisted diffusion bonding of 5754 aluminum alloy to coated high strength steels, Materials and Design (2013), doi: http://dx.
Al-Si alloys and sodium aluminum fluorides were obtained by reduction of Sodium-Fluosilicate (S.F... more Al-Si alloys and sodium aluminum fluorides were obtained by reduction of Sodium-Fluosilicate (S.F) with Al powder and molten aluminum. Different factors affecting the composition of the produced Al-Si alloys are studied. These factors are sodium fluosilicate to aluminum weight ratio, Al powder to S.F weight ratio and reaction time. The produced Al-Si alloys are self-modified due to sodium fluoride existence in the reaction's bath, which changed the morphology of Si crystals. This modification process assists in improving the mechanical properties. Microstructure examination, chemical analysis, x-ray diffraction, and Differential Thermal Analysis (DTA) are performed to characterize the as received materials and the produced alloys. The results indicated that the mechanism of the reaction was taken place as follows; when S.F is added to Al, the S.F decomposes to produce SiF4 gas which reduced in the presence of Al powder to silicon ion. The silicon ions combine with Al to form the Al-Si alloy and the fluorine ions react with Al and the residue of sodium fluoride to produce cryolite. The produced Al-Si alloy in this study is a high quality co
A porous surface of Ti–HA composite was successfully fabricated by pulsed current activated sinte... more A porous surface of Ti–HA composite was successfully fabricated by pulsed current activated sintering (PCAS), followed by leaching using diluted H3PO4. The Ti and HA powders were mixed at different contents of the HA, Ti-5, 10, 30 and 40 wt% HA powders. The mixed powders were pressed in a coated graphite die using pulsed current activated sintering (PCAS) under pressure of 60 MPa at temperature of 1000 °C for 5 min. The sintered Ti–HA specimens were immersed in the eight kinds of leaching solutions at room temperature for 24 h. The leached specimen’s surfaces were characterized using XRD, SEM, EDX and Rockwell hardness. The XRD patterns after sintering show that many phases were detected at the sintered specimen surfaces such as; Ti2O, CaO, CaTiO3, TixPy in addition to the remaining Ti and HA. Furthermore, the high concentration H3PO4 leaching solution is more efficient than the low concentration. Also the produced porous surfaces of Ti–HA materials containing more than 30% HA have a low relative density and hardness than the commercial Ti–6Al–4V ELI alloy. In a word, the presence of porous surface coated by HA will promote the nucleation of the biological apatite created with the human tissue and increase the bonding between them. So, the produced porous materials are considered so easy for the muscle cells to permeate after transplanted with high coherence.
In this study the optimum parameters affecting the preparation of aluminum foam from recycled alu... more In this study the optimum parameters affecting the preparation of aluminum foam from recycled aluminum were studied, these parameters are: temperature, CaCO3 to aluminum scrap wt. ratio as foaming agent, Al2O3 to aluminum scrap wt. ratio as thickening agent, and stirring time. The results show that, the optimum parameters are the temperature ranged from 800 to 850oC, CaCO3 to aluminum scrap wt. ratio was 5%, Al2O3 to aluminum scrap wt. ratio was 3% and stirring time was 45 second with stirring speed 1200 rpm. The produced foam apparent densities ranged from 0.40-0.60 g/cm3. The microstructure of aluminum foam was examined by using SEM, EDX and XRD, the results show that, the aluminum pores were uniformly distributed along the all matrices and the cell walls covered by thin oxide film.