1) The document describes a study where mechanical alloying was used to synthesize nanocrystalline MoSi2 powder directly from molybdenum oxide (MoO3) and silicon (Si) powders.
2) X-ray diffraction analysis showed that within 6 hours of milling, MoO3 was fully converted to MoO2, and after 17 hours milling, peaks indicated the presence of both α and β phases of MoSi2 as well as Mo.
3) After 50 hours of milling, calculations showed the MoSi2 crystallite sizes were less than 100 nm, and the β-MoSi2 phase transformed to the α-MoSi2 phase.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals
numerical investigation on induced residual stress of al albite metal matrix ...INFOGAIN PUBLICATION
The aim of the work was to investigate residual stress formed during fabrication of Al/albite metal matrix composites (MMCs) using finite element analysis. Optical images of MMCs were extracted from scanning electron microscope (SEM) after fabrication by stir-casting. The collected images and properties were used to determine residuals stresses at the interface using COMSOL multi physics tool. The imported MMCs images modelled and meshed for 5458, 6318 and 7149 elements for 5%, 10% and 15% particle reinforced composites respectively. Geometrical and thermal constraints are applied at the boundaries and difference in temperature T 620 C as a thermal constraint. FE results in the COMSOL multi physics show that residual stress in composites material tested are in the range of 1.55 MPa to 2.84 MPa. Al/albite with 15% albite reinforcement possesses lowest residual stress formation in all 27 cases studied with value of 1.55 MPa
Preparation and Investigation on Properties of Cryogenically Solidified Nano ...IJERA Editor
In the present work, AL-alloy containing 12% silicon (LM 13) matrix nano composites were fabricated in sand moulds by using copper end blocks of copper end chill thickness 10 &15 nm with cryogenic effect . The size of the reinforcement (NanoZro2) ranges from 50-80nm being added ranges from 3 to 15 wt % in steps of 3 wt % . Cryogenically solidified Nano Metal Matrix Composites were compressed by using hydraulic compression machine. Specimens were prepared according to ASTM standards and tested for their strength, hardness and fracture toughness. Micro structural studies of the fabricated Nano Composites indicate that there is uniform distributions of reinforcements in the matrix materials (LM 13). An increasing trend of hardness, UTS & fracture toughness has been observed. The best results have been obtained at 12 wt %. The results were further justified by comparing two copper end chill thickness 10 &15 mm. Finally the Volumetric Heat Capacity of the cryo-chill is identified as an important parameter which affects mechanical properties.
Dry Sliding Wear Behaviour of Rheocat Al-5.7Si-2Cu-0.3Mg AlloyDr. Manal Abdullatif
In this study, the effect of improved microstructure of Al-5.7Si-2Cu-0.3Mg alloys by using semisolid process on hardness and dry sliding wear behaviour were investigated. The microstructures of conventional cast alloy were totally dendritic, while in rheocasting the dendrit-ic transfer to fine globular microstructures after using cooling slope casting. Tribological tests were carried out by using a pin-on-disc apparatus in dry sliding conditions. Wear tests were at low sliding speed 1ms-1 ,applied load at 50N and three different sliding distance (i.e., 1.8Km, 5.4Km and 9Km) respectively. An optical microscope and a scanning electron microscope were used to examine the micro-structure and to understand the wear mechanism on the worn surface of both samples. The results showed that, the wear resistance of rheocast alloy was improved and higher than that those produce by conventional casting. The volume loss of rheocast alloy show reduc-tion more than 18% at 1.8Km and 10% at 9Km compared to as-cast alloy. Moderate wear regimes were appeared in both alloys, accord-ing to the range of wear rate. The friction coefficient had increased due to increase in the contact point between pin and disc materials. The dominant wear mechanism for conventional and rheocasting alloys was adhesion wear and abrasive wear respectively.
Investigation of the distribution of lead in three different combinations of ...Rautomead Limited
The main objective of this paper was to assess three leaded
brass samples (pending application with Copper Development
Association) using optical microscopy and mass
spectrometry to compare the distribution of lead. Based on
the mass spectrometry data, a great deal of variation was
not found within each of the samples based on five different
sample locations. Optical microscopy, scanning electron
microscopy and energy-dispersive X-ray spectroscopy
confirmed that the lead was homogenously distributed in
brass.
Alumina-Based Composites Reinforced With Ductile ParticlesIJRES Journal
Al2O3/Metal composite ceramics were fabricated by the use of mechanical milling and pressureless sintering. Al2O3 + 10 vol.% of La, Mn, Si or Y were mixed and milled during 12 h at 300 rpm in a horizontal mill, then with the powder mixture it was conformed cylindrical samples by uniaxial pressing using 300 MPa. Pressed samples were sintered during 2 h in an electrical furnace at 1500°C. During sintered it was used an argon atmosphere inside the furnace in order to inhibit metal oxidation. XRD results indicate that alumina and metals retain its crystalline structure. Reached density by samples is small and less than 90%. Scanning electron microscopy observations show alumina’s microstructure with very fine and homogeneous distributions of metal particles. Both the Mn and Si are not suitable metals to improve the mechanical properties of alumina, in particular the fracture toughness. Considered rare earth metals such as yttrium and lanthanum, have yielded favorable results in improving the fracture toughness of the alumina. However, it should be made more dense materials with them to better explore this potential.
EFFECT OF ANTIMONY ADDITION RELATIVE TO MICROSTRUCTURE AND MECHANICAL PROPERT...Rautomead Limited
It is well documented that the addition of antimony in pure lead increases tensile strength and reduced elongation. The goal of the present work is to identify the cause of these phenomena by investigation of the effects of the addition of Sb (1.25%) on the structure of pure continuously cast lead and lead alloy rods. The microstructure and morphology of both pure lead and lead 1.25% antimony were examined by digital optical microscope and scanning electron microscope respectively. Energy Dispersive X-ray Spectroscopy (EDX) was used to identify alloying elements. The results showed that the effect of additions of antimony on mechanical properties of lead-antimony alloys is mainly due to the solid solubility of the antimony element. Homogenized distribution of the antimony results in a decrease in the grain size of the pure lead. These smaller grains mean higher strength so long as there is a homogeneous grain structure
Characteristics of Hypoeutectic Cu-Zr Alloy Rods Manufactured by Vertical Upw...Rautomead Limited
The focus in this study is therefore on applying a vertical upwards continuous casting (VUCC) mass-production
method to the pilot-scale manufacturing of Cu-Zr alloy rods. The microstructure and physical characteristics of these
VUCC rods were subsequently investigated and compared with rods produced by CMC. In addition, the wire-drawing
capability of the VUCC rods was examined, and the adaptability of the VUCC method to the mass production of
hypoeutectic Cu-Zr alloys was fully investigated.
2.
Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...IJERA Editor
In this study, a series of manganese (Mn)-doped Cobalt oxide (Co3O4)thin films were deposited on steel substrate by the sol-gel spin coat method and investigated the influence of doping concentrations of Mn in Cobalt ranging from 0.001% to 1% on physical, structural and morphological properties of Co3O4 thin films. Cobalt acetate[(CH3COO)2Co.4H2O], Mn acetate [C4H6MnO4.4H2O] and Isopropyl alcohol were used as starting material, dopant source and reagent respectively.X-ray diffraction analysis indicated that pureCo3O4 thin film iscrystallinein nature andcubic phase with [400] preferential orientation.For Mn doped films, three new peaks corresponding to the planes [310], [320] and [420] of orthorhombic MnO2 phase were observed.SEM micrographs showed that incorporation of Mn in Co site was found to influence the surface morphology of the films. All the films showed tetragonal shaped grains. TheEDAXanalysis revealedthe amount of Mn element in the sample increased with increasing dopant concentration.
SiC and ZrO2 Weigh Percentage Effects on Microstructure of Al Based Matrix Co...INFOGAIN PUBLICATION
SiC and ZrO2 particle are succesfully reaction synthesized from powder of Al, ZrO2 and SiC using spark plasma sintering method. The XRD of sintered composite and microstructure of the aas-sintered products. With the ZrO2 content increasing, the grains are remarkably refined and the and the ZrO2 and nano SiC particles are dispersing more uniformly in Al matrix, forming a homogeneous structure with the least porosity.
Modification of Recycled Al-332 Alloy Using Manganese DioxideIJERA Editor
Aluminum and its alloys are commercially available materials for both domestic (cooking utensils, beverages can) and industrial applications (automobile and aircraft structural parts). This study presented the effect of the use of manganese dioxide (MnO2), obtained from discarded dry cell batteries on the features and formation of pores in recycled pistons (Al-332 alloy). 3kg of recycled Al-332 alloy was obtained in form of ingot. 150 g of the ingot was re-melted and the molten alloy was treated with 2 to 12g of MnO2. The molten alloy was stirred gently for 1 minute, sand cast and normalized. Parts of the cast samples were used for microstructural analysis, tensile strength and hardness test following standard test procedures in accordance with ASTM E8M-91 standards (1992). The distribution of pores present in the cast alloys were studied using fractal analysis and spatial point pattern method (SPP). The hardness, tensile strength, average fractal dimensions and sphericities were related to the amount of MnO2. The micrographs revealed an absolute reduction in pores at 8gram addition of MnO2. Maximum hardness and tensile values of 50.8BHN and 65.01MN/m2 were obtained at 8 g addition of MnO2, above which there is decrease in properties of the material. The weighted average fractal dimension and sphericity for as-cast and sample treated with 8 g of MnO2 are 1.3276 and 0.3357; 1.0050 and 0.9918 respectively. Spatial point pattern revealed that the pores in the samples are randomly distributed.
A Study on Mechanical and Tribological Properties of Magnesium Alloy AZ31 Rei...ijsrd.com
This work deals with fabricating or producing magnesium based metal matrix composite and then studying its mechanical and tribological properties such as microstructure, tensile strength, impact strength and wear behavior of produced test specimen. In the present study a modest attempt has been made to develop magnesium based MMCs with reinforcing material, with an objective to develop a conventional low cast method of producing MMCs and to obtain homogeneous dispersion of reinforced material. To achieve this objective stir casting technique has been adopted. An Alloy similar to commercially available composition of AZ31 and SiC, Al2O3 has been chosen as matrix and reinforcing material respectively. Experiment has been conducted by varying weight fraction of 3% SiC and 1% Al2O3 & 1% SiC and 3% Al2O3 in matrix metal. The result shown that tensile strength, impact strength, wear resistance is good in matrix metal as compared to used weight compositions of SiC and Al2O3 in the composites.
Microstructure Degradation after Prolonged Exploitation of Heatresistant Ste...IJMER
Metallographic testing of material microstructure represents important method for
characterization of material behavior. In case of heat resistant steels that are used for steam lines and
boiler components of thermal power plants for a long period of service time, under the influence of
mechanical and thermal loads their microstructure will be changed. As a result, it will have significant
influence on mechanical properties of such material. Metallographic testing can be used for following
of microstructure evolution
and estimation of components further safe service time, but at the same time knowing of changes in
material microstructure is necessary for better understanding of mechanical properties degradation
mechanism. Microstructure as indicator of material degradation of heat resistant streamline steel
14MoV6-3 after almost 200.000 hours of exploitation at steam temperature 540 °C and pressure
13,5MPa has been investigated in this paper. It is necessary to emphasize that this streamline has been
designed for service life time of 100.000 hours for mentioned steam parameters.
TRIBOLOGICAL CHARACTERISTICS OF ALUMINIUM HYBRID COMPOSITES REINFORCED WITH S...Blaza Stojanovic
This paper presents tribological characteristics of hybrid composites with aluminium
matrix, reinforced with silicon carbide (SiC) and graphite (Gr). Newly
formed Al/SiC/Gr hybrid composites are the combination of the two different hybrid
materials. Namely, hard particles of silicon carbide increase the hardness and
resistance to wear, while soft particles of graphite improve lubrication and reduce
friction coefficient and wear. It is possible to obtain Al/SiC/Gr hybrid composites
by different methods of casting. Tribological tests show that load, sliding speed,
sliding distance, content and size of reinforcement particles influence the size
and the type of wear and friction coefficient of Al/SiC/Gr hybrid composites with
aluminium matrix.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals
numerical investigation on induced residual stress of al albite metal matrix ...INFOGAIN PUBLICATION
The aim of the work was to investigate residual stress formed during fabrication of Al/albite metal matrix composites (MMCs) using finite element analysis. Optical images of MMCs were extracted from scanning electron microscope (SEM) after fabrication by stir-casting. The collected images and properties were used to determine residuals stresses at the interface using COMSOL multi physics tool. The imported MMCs images modelled and meshed for 5458, 6318 and 7149 elements for 5%, 10% and 15% particle reinforced composites respectively. Geometrical and thermal constraints are applied at the boundaries and difference in temperature T 620 C as a thermal constraint. FE results in the COMSOL multi physics show that residual stress in composites material tested are in the range of 1.55 MPa to 2.84 MPa. Al/albite with 15% albite reinforcement possesses lowest residual stress formation in all 27 cases studied with value of 1.55 MPa
Preparation and Investigation on Properties of Cryogenically Solidified Nano ...IJERA Editor
In the present work, AL-alloy containing 12% silicon (LM 13) matrix nano composites were fabricated in sand moulds by using copper end blocks of copper end chill thickness 10 &15 nm with cryogenic effect . The size of the reinforcement (NanoZro2) ranges from 50-80nm being added ranges from 3 to 15 wt % in steps of 3 wt % . Cryogenically solidified Nano Metal Matrix Composites were compressed by using hydraulic compression machine. Specimens were prepared according to ASTM standards and tested for their strength, hardness and fracture toughness. Micro structural studies of the fabricated Nano Composites indicate that there is uniform distributions of reinforcements in the matrix materials (LM 13). An increasing trend of hardness, UTS & fracture toughness has been observed. The best results have been obtained at 12 wt %. The results were further justified by comparing two copper end chill thickness 10 &15 mm. Finally the Volumetric Heat Capacity of the cryo-chill is identified as an important parameter which affects mechanical properties.
Dry Sliding Wear Behaviour of Rheocat Al-5.7Si-2Cu-0.3Mg AlloyDr. Manal Abdullatif
In this study, the effect of improved microstructure of Al-5.7Si-2Cu-0.3Mg alloys by using semisolid process on hardness and dry sliding wear behaviour were investigated. The microstructures of conventional cast alloy were totally dendritic, while in rheocasting the dendrit-ic transfer to fine globular microstructures after using cooling slope casting. Tribological tests were carried out by using a pin-on-disc apparatus in dry sliding conditions. Wear tests were at low sliding speed 1ms-1 ,applied load at 50N and three different sliding distance (i.e., 1.8Km, 5.4Km and 9Km) respectively. An optical microscope and a scanning electron microscope were used to examine the micro-structure and to understand the wear mechanism on the worn surface of both samples. The results showed that, the wear resistance of rheocast alloy was improved and higher than that those produce by conventional casting. The volume loss of rheocast alloy show reduc-tion more than 18% at 1.8Km and 10% at 9Km compared to as-cast alloy. Moderate wear regimes were appeared in both alloys, accord-ing to the range of wear rate. The friction coefficient had increased due to increase in the contact point between pin and disc materials. The dominant wear mechanism for conventional and rheocasting alloys was adhesion wear and abrasive wear respectively.
Investigation of the distribution of lead in three different combinations of ...Rautomead Limited
The main objective of this paper was to assess three leaded
brass samples (pending application with Copper Development
Association) using optical microscopy and mass
spectrometry to compare the distribution of lead. Based on
the mass spectrometry data, a great deal of variation was
not found within each of the samples based on five different
sample locations. Optical microscopy, scanning electron
microscopy and energy-dispersive X-ray spectroscopy
confirmed that the lead was homogenously distributed in
brass.
Alumina-Based Composites Reinforced With Ductile ParticlesIJRES Journal
Al2O3/Metal composite ceramics were fabricated by the use of mechanical milling and pressureless sintering. Al2O3 + 10 vol.% of La, Mn, Si or Y were mixed and milled during 12 h at 300 rpm in a horizontal mill, then with the powder mixture it was conformed cylindrical samples by uniaxial pressing using 300 MPa. Pressed samples were sintered during 2 h in an electrical furnace at 1500°C. During sintered it was used an argon atmosphere inside the furnace in order to inhibit metal oxidation. XRD results indicate that alumina and metals retain its crystalline structure. Reached density by samples is small and less than 90%. Scanning electron microscopy observations show alumina’s microstructure with very fine and homogeneous distributions of metal particles. Both the Mn and Si are not suitable metals to improve the mechanical properties of alumina, in particular the fracture toughness. Considered rare earth metals such as yttrium and lanthanum, have yielded favorable results in improving the fracture toughness of the alumina. However, it should be made more dense materials with them to better explore this potential.
EFFECT OF ANTIMONY ADDITION RELATIVE TO MICROSTRUCTURE AND MECHANICAL PROPERT...Rautomead Limited
It is well documented that the addition of antimony in pure lead increases tensile strength and reduced elongation. The goal of the present work is to identify the cause of these phenomena by investigation of the effects of the addition of Sb (1.25%) on the structure of pure continuously cast lead and lead alloy rods. The microstructure and morphology of both pure lead and lead 1.25% antimony were examined by digital optical microscope and scanning electron microscope respectively. Energy Dispersive X-ray Spectroscopy (EDX) was used to identify alloying elements. The results showed that the effect of additions of antimony on mechanical properties of lead-antimony alloys is mainly due to the solid solubility of the antimony element. Homogenized distribution of the antimony results in a decrease in the grain size of the pure lead. These smaller grains mean higher strength so long as there is a homogeneous grain structure
Characteristics of Hypoeutectic Cu-Zr Alloy Rods Manufactured by Vertical Upw...Rautomead Limited
The focus in this study is therefore on applying a vertical upwards continuous casting (VUCC) mass-production
method to the pilot-scale manufacturing of Cu-Zr alloy rods. The microstructure and physical characteristics of these
VUCC rods were subsequently investigated and compared with rods produced by CMC. In addition, the wire-drawing
capability of the VUCC rods was examined, and the adaptability of the VUCC method to the mass production of
hypoeutectic Cu-Zr alloys was fully investigated.
2.
Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...IJERA Editor
In this study, a series of manganese (Mn)-doped Cobalt oxide (Co3O4)thin films were deposited on steel substrate by the sol-gel spin coat method and investigated the influence of doping concentrations of Mn in Cobalt ranging from 0.001% to 1% on physical, structural and morphological properties of Co3O4 thin films. Cobalt acetate[(CH3COO)2Co.4H2O], Mn acetate [C4H6MnO4.4H2O] and Isopropyl alcohol were used as starting material, dopant source and reagent respectively.X-ray diffraction analysis indicated that pureCo3O4 thin film iscrystallinein nature andcubic phase with [400] preferential orientation.For Mn doped films, three new peaks corresponding to the planes [310], [320] and [420] of orthorhombic MnO2 phase were observed.SEM micrographs showed that incorporation of Mn in Co site was found to influence the surface morphology of the films. All the films showed tetragonal shaped grains. TheEDAXanalysis revealedthe amount of Mn element in the sample increased with increasing dopant concentration.
SiC and ZrO2 Weigh Percentage Effects on Microstructure of Al Based Matrix Co...INFOGAIN PUBLICATION
SiC and ZrO2 particle are succesfully reaction synthesized from powder of Al, ZrO2 and SiC using spark plasma sintering method. The XRD of sintered composite and microstructure of the aas-sintered products. With the ZrO2 content increasing, the grains are remarkably refined and the and the ZrO2 and nano SiC particles are dispersing more uniformly in Al matrix, forming a homogeneous structure with the least porosity.
Modification of Recycled Al-332 Alloy Using Manganese DioxideIJERA Editor
Aluminum and its alloys are commercially available materials for both domestic (cooking utensils, beverages can) and industrial applications (automobile and aircraft structural parts). This study presented the effect of the use of manganese dioxide (MnO2), obtained from discarded dry cell batteries on the features and formation of pores in recycled pistons (Al-332 alloy). 3kg of recycled Al-332 alloy was obtained in form of ingot. 150 g of the ingot was re-melted and the molten alloy was treated with 2 to 12g of MnO2. The molten alloy was stirred gently for 1 minute, sand cast and normalized. Parts of the cast samples were used for microstructural analysis, tensile strength and hardness test following standard test procedures in accordance with ASTM E8M-91 standards (1992). The distribution of pores present in the cast alloys were studied using fractal analysis and spatial point pattern method (SPP). The hardness, tensile strength, average fractal dimensions and sphericities were related to the amount of MnO2. The micrographs revealed an absolute reduction in pores at 8gram addition of MnO2. Maximum hardness and tensile values of 50.8BHN and 65.01MN/m2 were obtained at 8 g addition of MnO2, above which there is decrease in properties of the material. The weighted average fractal dimension and sphericity for as-cast and sample treated with 8 g of MnO2 are 1.3276 and 0.3357; 1.0050 and 0.9918 respectively. Spatial point pattern revealed that the pores in the samples are randomly distributed.
A Study on Mechanical and Tribological Properties of Magnesium Alloy AZ31 Rei...ijsrd.com
This work deals with fabricating or producing magnesium based metal matrix composite and then studying its mechanical and tribological properties such as microstructure, tensile strength, impact strength and wear behavior of produced test specimen. In the present study a modest attempt has been made to develop magnesium based MMCs with reinforcing material, with an objective to develop a conventional low cast method of producing MMCs and to obtain homogeneous dispersion of reinforced material. To achieve this objective stir casting technique has been adopted. An Alloy similar to commercially available composition of AZ31 and SiC, Al2O3 has been chosen as matrix and reinforcing material respectively. Experiment has been conducted by varying weight fraction of 3% SiC and 1% Al2O3 & 1% SiC and 3% Al2O3 in matrix metal. The result shown that tensile strength, impact strength, wear resistance is good in matrix metal as compared to used weight compositions of SiC and Al2O3 in the composites.
Microstructure Degradation after Prolonged Exploitation of Heatresistant Ste...IJMER
Metallographic testing of material microstructure represents important method for
characterization of material behavior. In case of heat resistant steels that are used for steam lines and
boiler components of thermal power plants for a long period of service time, under the influence of
mechanical and thermal loads their microstructure will be changed. As a result, it will have significant
influence on mechanical properties of such material. Metallographic testing can be used for following
of microstructure evolution
and estimation of components further safe service time, but at the same time knowing of changes in
material microstructure is necessary for better understanding of mechanical properties degradation
mechanism. Microstructure as indicator of material degradation of heat resistant streamline steel
14MoV6-3 after almost 200.000 hours of exploitation at steam temperature 540 °C and pressure
13,5MPa has been investigated in this paper. It is necessary to emphasize that this streamline has been
designed for service life time of 100.000 hours for mentioned steam parameters.
TRIBOLOGICAL CHARACTERISTICS OF ALUMINIUM HYBRID COMPOSITES REINFORCED WITH S...Blaza Stojanovic
This paper presents tribological characteristics of hybrid composites with aluminium
matrix, reinforced with silicon carbide (SiC) and graphite (Gr). Newly
formed Al/SiC/Gr hybrid composites are the combination of the two different hybrid
materials. Namely, hard particles of silicon carbide increase the hardness and
resistance to wear, while soft particles of graphite improve lubrication and reduce
friction coefficient and wear. It is possible to obtain Al/SiC/Gr hybrid composites
by different methods of casting. Tribological tests show that load, sliding speed,
sliding distance, content and size of reinforcement particles influence the size
and the type of wear and friction coefficient of Al/SiC/Gr hybrid composites with
aluminium matrix.
Microstructural Characterization of Co-Cr-Mo-W Alloy as Casting for Odontolog...IJERA Editor
Interest in the analysis and material characterization is rising due to the necessity of the adequate material selection based on system performance in study. The analysis and knowledge of the microstructure and the mechanical properties of any material are of utmost importance since it aims primarily to estimate the performance during the material life span, minimizing the possibility of degradation and undesirable flaws during product utilization. Co-Cr-Mo-W alloys have been well accepted in odontology as prosthesis material, due to its high mechanical resistance, good corrosion resistance and exceptional biocompatibility properties. This study aims to characterize the microstructure of a cobalt based alloy (Co-Cr-Mo-W) obtained through vacuum casting process. Optical microscopy, electronic sweeping microscopy and X-ray were employed and Vickers hardness test with loads of 100 gf, 500 gf and 1000 gf during 10 s. Microstructure casting is characterized by a Co-fcc dendritic matrix with a secondary phase, as well as M23C6 precipitate carbides in the interdendritics zones and grain boundaries. The precipitation of carbides represents the main device of strengthening in the cast state for these types of alloys and is also responsible for its lower mechanical properties. The material attained hardness between 25 and 35 HRC, meeting the ASTM F75 standards.
Diffusion Bonding of Semi-Solid (SSM 356) Cast Aluminum AlloyIJMER
A new technique to achieve the globular weld structure of SSM 356 aluminum alloy was
conducted. The effect of joining parameters on the microstructure and mechanical properties of diffusion
bonding butt joints of semi-solid SSM 356 aluminum alloy was investigated by conditions as follows:
compressive pressure at 0.4, 0.9, 1.8, 2.4 and 2.7 MPa, with holding time 3 hours and temperature at
495oC under argon atmosphere at 4 liters per minute. The results showed that the compressive pressure
1.8 MPa, with holding time 3 hours and temperature 495oC, under argon atmosphere provided the highest
joint strength to 124.48 MPa. In addition, the results of the investigation have shown that the joint
efficiency was 72 percent compared with base metal and microstructure in weld zone (WZ) after welding
becomes globular structure. This microstructure, similar to the original structure of the base material, is a
globular structure but the grain size can grow at a higher temperature
INVESTIGATION OF OPTIMIZED PROCESS PARAMETERS ON DENSIFICATION OF SAMARIUM CO...ijeljournal
Samarium Cobalt 2:17 series (Sm2Co17) magnet is prepared by powder metallurgy technique. Different parameters for sintering and heat treatment process such as sintering time, temperature, furnace atmosphere and heating rate were tested in order to achieve the highest density for Samarium Cobalt 2:17 series that could be obtained. To analyze and evaluate the microstructure and particle size of fabricated magnets, scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests were used. Results show that sintering temperatures and furnace atmosphere are among the most important parameters that affecting on the density of the samples and consequently the magnetic properties. It is showed that the highest density of 7.98 g/cm3 (%95 of theoretical density) has been obtained from initial particles with the size of 3 to 6 µm and sintering temperature of 11950C with a rate of 17˚C/min for 1 hr in vacuum condition.
Investigation of Optimized Process Parameters on Densification of Samarium Co...ijeljournal
Samarium Cobalt 2:17 series (Sm2Co17) magnet is prepared by powder metallurgy technique. Different parameters for sintering and heat treatment process such as sintering time, temperature, furnace atmosphere and heating rate were tested in order to achieve the highest density for Samarium Cobalt 2:17 series that could be obtained. To analyze and evaluate the microstructure and particle size of fabricated magnets, scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests were used. Results show that sintering temperatures and furnace atmosphere are among the most important parameters that affecting on the density of the samples and consequently the magnetic properties. It is showed that the highest density of 7.98 g/cm3 (%95 of theoretical density) has been obtained from initial particles with the size of 3 to 6 µm and sintering temperature of 11950C with a rate of 17˚C/min for 1 hr in vacuum condition.
Investigation of Optimized Process Parameters on Densification of Samarium Co...ijeljournal
Samarium Cobalt 2:17 series (Sm2Co17) magnet is prepared by powder metallurgy technique. Different parameters for sintering and heat treatment process such as sintering time, temperature, furnace atmosphere and heating rate were tested in order to achieve the highest density for Samarium Cobalt 2:17 series that could be obtained. To analyze and evaluate the microstructure and particle size of fabricated magnets, scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests were used. Results show that sintering temperatures and furnace atmosphere are among the most important parameters that affecting on the density of the samples and consequently the magnetic properties. It is showed that the highest density of 7.98 g/cm3 (%95 of theoretical density) has been obtained from initial particles with the size of 3 to 6 µm and sintering temperature of 11950C with a rate of 17˚C/min for 1 hr in vacuum condition
Investigation of Optimized Process Parameters on Densification of Samarium Co...ijeljournal
Samarium Cobalt 2:17 series (Sm2Co17) magnet is prepared by powder metallurgy technique. Different
parameters for sintering and heat treatment process such as sintering time, temperature, furnace
atmosphere and heating rate were tested in order to achieve the highest density for Samarium Cobalt 2:17
series that could be obtained. To analyze and evaluate the microstructure and particle size of fabricated magnets, scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests were used. Results show that sintering temperatures and furnace atmosphere are among the most important parameters that affecting on the density of the samples and consequently the magnetic properties. It is showed that the
highest density of 7.98 g/cm3 (%95 of theoretical density) has been obtained from initial particles with the size of 3 to 6 µm and sintering temperature of 11950C with a rate of 17˚C/min for 1 hr in vacuum condition.
INVESTIGATION OF OPTIMIZED PROCESS PARAMETERS ON DENSIFICATION OF SAMARIUM CO...ijeljournal
The aim of this study is to investigate the effect of different process parameters on densification of
Samarium Cobalt 1:5 series (SmCo5) magnet by powder metallurgy technique. Different parameters for
sintering and heat treatment process such as particle size, load of press, sintering time and temperature,
furnace atmosphere and heating rate were tested in order to achieve the highest density. To analyze and
evaluate the microstructure and particle size of manufactured magnets scanning electron microscopy
(SEM) and X-ray diffraction (XRD) tests were conducted. Results of different tests showed that sintering
temperature as well as furnace atmosphere is among the most important parameters affecting on final
density of the samples. Investigations illustrated that highest density could be obtained with the sintering
of green bodies which made from initial particles with the size of 3 to 6 µm in vacuum condition at 1135˚C
for 30 min by rapid heating at the shortest time.
Fundamentals, synthesis and applications of Al2O3-ZrO2 compositesTANDRA MOHANTA
When the word “Ceramic” comes to our mind, we usually associate them with plates, saucers, cups and mugs. But, the word “Ceramic” encompasses more than just the word “plates” or “saucers”. Indeed, ceramic materials are hard and inherently brittle, but this is just the tip of the iceberg. They have multifarious properties and have acquired a status of high technical importance in the field of scientific research. Ceramics are the soul of the modern day’s structural applications owing to their high mechanical and thermal stability under different challenging conditions. They exhibit remarkable properties such as high hardness, high wear resistance, high corrosion resistance, high elastic modulus, high melting point and the ability to retain high strength at elevated temperatures. Alumina (Al2O3) is one such remarkable ceramic material known for its unique optical, mechanical and electrical properties. But the brittle nature of Al2O3 limits its use in certain engineering applications. Therefore, the strength of Al2O3 and Al2O3- based ceramics can be enhanced by tailoring the microstructural design through the application of strategic techniques that may involve secondary phase particle inclusion (such as Zirconia, ZrO2)
Microwave Assisted Sol Gel Synthesis of Magnesium Oxide(Mgo)IJERDJOURNAL
ABSTRACT: Magnesium oxide (MgO) nanoparticles have been synthesized by Microwave assisted Sol gel synthesis method by using the precursors citric acid (C2O4H2) and magnesium chloride (Mgcl2.6H2O). It is a simple, novel and cost effective method. The structure, morphology and crystalline phase of the magnesium oxide nanocrystals have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD).Presence of functional groups and optical characters are analyzed by using FTIR and UV- visible techniques
Influence of Ruthenium doping on Structural and Morphological Properties of M...IJERA Editor
The present work examines the effect of Ru doping on MoO3 thin films on steel substrate deposited by Sol-gel spin coat method. The annealing temperature was 6000C for pure MoO3 and 8000C for Ru doped thin films. The doping concentration of Ru was varied from 10 to 50wt%. The influence of Ru doping on structural and morphological properties of MoO3 thin films were studied. The XRD revealed that all films are highly crystalline in nature with monoclinic phase for molybdenum peaks. In the doped XRD pattern some new peaks were observed and are matched with ruthenium orthorhombic phase indicating an incorporation of dopant in pure molybdenum oxide. The same is confirmed with the compositional analysis by EDAX. The SEM images of the MoO3 resemble a rod like surface with porous morphology. Incorporation of Ru ions in molybdenum oxide decreases the length of the rods and vanishes after 40wt%. Tetragonal grain size increases from 20wt% of Ru and becomes maximum at 50wt% of Ru doped thin films
Influence of Ruthenium doping on Structural and Morphological Properties of M...IJERA Editor
The present work examines the effect of Ru doping on MoO3 thin films on steel substrate deposited by Sol-gel spin coat method. The annealing temperature was 6000C for pure MoO3 and 8000C for Ru doped thin films. The doping concentration of Ru was varied from 10 to 50wt%. The influence of Ru doping on structural and morphological properties of MoO3 thin films were studied. The XRD revealed that all films are highly crystalline in nature with monoclinic phase for molybdenum peaks. In the doped XRD pattern some new peaks were observed and are matched with ruthenium orthorhombic phase indicating an incorporation of dopant in pure molybdenum oxide. The same is confirmed with the compositional analysis by EDAX. The SEM images of the MoO3 resemble a rod like surface with porous morphology. Incorporation of Ru ions in molybdenum oxide decreases the length of the rods and vanishes after 40wt%. Tetragonal grain size increases from 20wt% of Ru and becomes maximum at 50wt% of Ru doped thin films
Low grade iron ores are often contaminated with relatively high percentage of different
impurity gangue minerals. The iron ores contaminated with manganese oxide and silica are hardly reducible
and consume more energy in the integrated steel plant. Therefore it is important to estimate and predict the
influence of manganese oxide, silica and temperature on the reduction yield of iron oxide using mathematical
model approach. In the current study, a 23
(three-parameters, two-levels)factorial design is applied on the
gaseous reduction experimental data of mixed oxides (Fe2O3-MnO2-SiO2) to build a linear regression model.
The calculations have been performed using Matlab program. The developed mathematical model indicated that
SiO2 and temperature have positive effect on the reduction yield of iron oxide. On the other hand, MnO2
exhibited the highest negative impact on the reduction yield of iron oxide followed by the interaction coefficient
of MnO2, SiO2 and temperature. The results of the developed mathematical model are fitted to the experimental
reduction data of mixed oxides.
The Effect of Bed Thickness and Cooling Time on the Rate of Copper Slag Cooli...CrimsonPublishersAMMS
The Effect of Bed Thickness and Cooling Time
on the Rate of Copper Slag Cooling, Case Study:Khatoonabad Copper Smelter Plant by Esmaeil Rahimi and Neda Mohaghegh in Aspects in Mining & Mineral Science
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Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
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Cosmetic shop management system project report.pdfKamal Acharya
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Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
2. Fig. 1. Equilibrium phase diagram of Mo–Si [4].
Experimental
In this investigation, mechanical alloying was performed under argon atmosphere in a high
energy ball milling at room temperature and speed of rotation (cup speed) of 600 rpm. MoO3 (99%,
100 µm) and Si (99%) powders were used as starting materials. The weight ratio of ball to powder
was selected as 33:1. The balls and vial were made of hardening steel. Samples for analysis were
removed by interrupting the ball mill at various intervals. Investigation of phases and products
evolution during ball milling has been performed by using a X-ray diffractometer (Philips Xpert
Professional) with 30 kV, 40 mA, 0.02 step size and 1 second per step with CoKα radiation (λ=1.78
Å). Also, crystallite size was evaluated using the scherrer and Williamson-Hall methods from the
line broadening of the diffraction lines, as follow [9]:
t =
. λ
θ
(Scherrer) (1)
BCosθ =
. λ
+ 2ηSinθ (Williamson-Hall) (2)
Where t is the crystallite average size (nm), λ the CoKα wave length (nm), B the diffraction peak
width at half maximum intensity (radian) and θ is the diffraction Bragg angle. The morphology of
the mechanically alloyed powders was monitored with a Scanning Electron Microscope (SEM).
Results and Discussion
Starting materials (MoO3 and Si powders) were accurately weighed according to the following
reaction and then mixed together and milled.
2MoO3 + 7Si → 2MoSi2 + 3SiO2 (3)
10 %mol. excess Si was added to compensate the probably losses during handling and milling.
Reaction (3) is in fact sum of the following partial reactions:
2MoO3 + Si → 2MoO2 + SiO2 (4)
2MoO2 + 2Si → 2Mo + 2SiO2 (5)
2Mo + 4Si → 2MoSi2 (6)
Advanced Materials Research Vols. 264-265 1365
3. Gibbs free energy changes for the reaction (3) were calculated using Eq. 7 [10] and found to be
-1496.2 kJ.mol-1
at room temperature which shows the reaction (3) is thermodynamically feasible in
the milling conditions.
∆G = -1505.9 + 32.5 T (kJ.mol-1
) (7)
Fig. 2 shows XRD patterns of the un-milled and milled powders mixture after different milling
times. As can be seen, by increasing the milling time, peaks of starting materials are broadened and
their intensities are decreased. This is obviously due to gradual decrease of crystallite sizes in
powder particles and transformation of crystalline structures to amorphous state. After 6 hours of
milling, almost all of the MoO3 is consumed and a mixture of Si, SiO2 and MoO2 forms. By further
milling, the intensity of Si peaks is decreased and for those of MoO2 is increased. Concurrently,
SiO2 is formed and its peaks are overlapped with those of MoO2. After 17 hours of milling, MoO2
also began to reduce and peaks of MoSi2 (both α and β phases) and Mo were detected. Mo peaks
cannot be observed clearly because of high mass absorption coefficient of synthesized phases.
Fig. 2. XRD patterns of the un-milled powder together with samples milled for different milling times.
Variations of crystallite sizes for Si, MoO2, MoSi2 (both α and β phases) has been shown in
Table 1. For α-MoSi2 and Si, the Williamson-Hall method was used, while for β-MoSi2 and MoO2,
the scherrer method was used due to the overlapping of peaks.
As can be seen, by increasing the milling time, the mean crystallite sizes of all powder
components decrease. Decrease in the crystallite sizes of powder components is due to the line
broadening of the diffraction lines, increase in lattice micro-strains and transformation of crystalline
structure to amorphous state.
An interesting phenomenon occurred during the milling operation was the conversion of β-
MoSi2 to α-MoSi2 after 50 hours of milling. Because of its meta-stable nature, β-MoSi2 phase
transforms to α-MoSi2 phase when its mean crystallite size reaches to a certain amount (almost 11
nm) [4]. After 50 hours of milling, the mean crystallite sizes were calculated to be 11 nm and 9 nm
for β-MoSi2 and α-MoSi2, respectively.
1366 Advances in Materials and Processing Technologies II
4. Table 1. Calculated mean crystallite sizes in the milled powder particles.
Table 2. shows the thermodynamic data for the starting materials and the reactions occur during
the mechanical alloying [10]. Calculation of the Gibbs free energy changes for the reactions shows
that they are all thermodynamically feasible at room temperature. Reaction (3) is extremely
exothermic and according to the ∆H298/Cp parameter, the mechanism of this reaction can be of
combustion type. It is noticeable that the exothermicity of a reaction is often characterized by the
ratio of the heat of formation to heat capacity at room temperature (∆H298/Cp). Typically,
∆H/Cp>2000 K is required for the propagation of a self-sustaining reaction [5]. This value for
reaction (3) is 5629.32 K [10]. The apparent activation energy for starting this reaction is not too
much, such that just after the beginning of the milling operation, reduction of MoO3 starts in
suitable locations of powders due to mechanical forces. Right after, due to release of the reactions
heat, temperature rises up to which the reaction between molybdenum and silicone starts concurrent
with MoO2 reduction reaction. The reaction between Mo and Si is also an exothermic one. Thus,
these factors provide the desirable thermodynamic conditions to form the β-MoSi2, because this
phase is stable at higher temperatures. However, this phase is meta stable at room temperature and
by further milling, it is expectable to transform to a stable state. This prediction is completely
consonant with XRD analysis. As can be seen from the XRD patterns (Fig. 2.), this phase (β-MoSi2)
is present until 50 hours of milling and it is expected to disappear with prolonged milling and
transform to α-MoSi2.
Table 2. Thermodynamic data for starting materials and reactions occur during the mechanical alloying at
room temperature [10].
SiO2 Si MoO3 Mo Reaction 4 Reaction 6 Reaction 3
∆S
[J/deg. mol]
41.5 18.8 77.8 28.6 -54.9 65.1 -32.5
∆H
[kJ/mol]
-910.9 ------ -745.2 ------ -930.5 -131.8 -1505.9
Cp
[J/deg. mol]
43.93 23.93 75.19 28.52 8.06 67.86 267.52
∆G
[kJ/mol]
----- ----- ----- ----- -314.14 -151.2 -1496.2
∆H298
/Cp
[K]
----- ----- ----- ----- ----- ----- 5629.32
Fig. 3 shows the SEM micrographs of the un-milled and milled powders after different milling
times. Fig 3(a) shows the morphology of un-milled sample. As seen in this image, MoO3 particles
have a blade-shaped morphology. Fig. 3(b) shows the powders morphology after 17 hours of
milling. Particles coalescence and formation of large agglomerates are obvious in this image.
MoO3/Si system is a brittle-brittle system and according to [5], the cold welding phenomenon does
not occur in these systems. Thus, the agglomeration might probably be due to Mo presence after 17
hours of milling in this system. So, the molybdenum soft particles act as welding agent and result in
Milling time
[h]
d(MoO2)
[nm]
d(Si)
[nm]
d(βMoSi2)
[nm]
d(αMoSi2)
[nm]
Strain η
[%]
6 16.6 49.2 --- ---- 0.275
12 --- 204 --- ---- 0.687
17 --- 15.2 32 48.2 ------
22 --- --- 17.6 26 0.36
28 --- --- 17.6 25.7 0.52
33 --- --- 12.5 19.2 0.64
50 --- --- 11 9 0.93
Advanced Materials Research Vols. 264-265 1367
5. the formation of agglomerates. Also, in brittle-brittle systems, when there is not any ductile
component like Mo, large agglomerates can be formed. This occurs during milling since the harder
(more brittle) component gets fragmented and embedded in the less brittle (softer) component (Fig.
3(c)). However, with prolonged milling, the agglomerates break down again into small particles
(Fig. 3(d)) because the final product (MoSi2) is formed and there is not any ductile Mo available to
result in welding of particles.
Fig. 3. SEM Micrographs of (a) un-milled sample and those milled for (b) 17, (c) 33 and (d) 50 hours.
Conclusion
The feasibility of MoSi2 synthesis by ball milling of mixtures MoO3 and Si powders at ambient
temperature was investigated. A MoSi2-SiO2 nanocomposite was successfully synthesized. From
the XRD studies on milled samples, it was shown that after 6 hours of milling, silicon can reduce
MoO3 to MoO2. Increased milling time resulted in peaks broadening and decreasing in peaks
intensity due to particles refining and increased lattice micro-strains. After 17 hours of milling,
peaks of MoSi2 (both α and β phases) and Mo were detected. Simultaneous formation of these two
phases is probably due to high intensity of milling operation and in such a condition, either α and/or
α + β molybdenum disilicide may form. An interesting phenomenon occurred during the milling
which was gradual conversion of β-MoSi2 to α-MoSi2 after 50 h of milling.
1368 Advances in Materials and Processing Technologies II
6. Acknowledgements
The authors would like to acknowledge the Iranian Nanotechnology Initiative for financial support
of this work.
References
[1] Ch. Gras, D. Vrel, E. Gaffet and F. Bernard, J. Alloys Compd Vol. 314 (2001), p. 240.
[2] L. Liu, F. Padella,W. Guo and M. Magini, Acta. Metall. Mater Vol.43 (1995), p. 3755.
[3] Z. Yao, J. Stiglich, and T.S. Sudarshan, J. Mater. Eng. Perf Vol. 8 (1999), p. 291.
[4] M. Zakeri, R. Yazdani-Rad, M.H. Enayati, M.R. Rahimipour and I. Mobasherpour, J. Alloys
Compd Vol. 430 (2007), p. 170.
[5] C. Suryanarayana, Prog. Mater. Sci Vol. 46 (2001), p. 1.
[6] C. H Lee, J. Ceram. Proc. Res Vol. 9 (2008), p. 321.
[7] S. C. Deevi and S. Deevi, Scr. Metall. Mater Vol. 33 (1995), p. 415.
[8] M. Sannia, R. Orru, J.E. Garay, G. Cao and Z.A. Munir, Mater. Sci. Eng. A Vol. 345 (2003), p.
270.
[9] B. D. Cullity, Elements of X-Ray Diffraction, second ed., Addison-esley Publishing, (1977).
[10] D. R. Gaskell, Introduction to the thermodynamics of materials, 4th ed, New York, London
Taylor and Francis, (2003).
Advanced Materials Research Vols. 264-265 1369
7. Advances in Materials and Processing Technologies II
10.4028/www.scientific.net/AMR.264-265
Mechanochemical Reduction of MoO3 Powder by Silicone to Synthesize Nanocrystalline MoSi2
10.4028/www.scientific.net/AMR.264-265.1364