This document summarizes a study on validating the Niyama criteria function for predicting porosity development in castings of the aluminium alloy AlSi7Mg. Eight test bars with varying dimensions were cast and analyzed. Computer simulations using the Niyama function were compared to the actual porosity levels found in the castings to evaluate the reliability of the model in predicting porosity for this alloy.
The document summarizes the synthesis, characterization, and AC conductivity of nickel-doped magnesium ferrite. Key findings include:
1) Magnesium nickel ferrites were synthesized via a sol gel technique and sintered at 1473 K. X-ray diffraction analysis revealed the presence of a nickel oxide phase along with the ferrite phase, indicating an almost stoichiometric (Mg,Ni)-ferrite phase was obtained.
2) Scanning electron microscopy images showed the (MgNi) ferrite had a regular, granular structure with well-connected grains and an average grain size of 0.7 micrometers.
3) The AC conductivity of the magnesium nickel ferrite increased with increasing frequency
THERCAST: A new 3D simulation model for complete chaining casted and forged i...TRANSVALOR S.A.
This document presents a new 3D simulation model for casting and forging ingots. It combines casting and forging simulation modules to track defects from casting through forging operations. The model uses finite element analysis to simulate heat transfer, fluid flow, and mechanical behavior during solidification and forging. Simulation results can provide insight into defect formation during casting and how defects evolve during subsequent forging to help optimize process parameters and improve final product quality.
The document discusses the characterization and numerical optimization of chromium-free nickel alloy filler materials for dissimilar welding between stainless steel SS304. Eight alloys with compositions ranging from 40-43.5% Ni, 4-20% Mo, 0-16% Co, 10% Cu, 22-25% Fe, 0.5% Al, 1% Ti, and 0.001% C were analyzed. JMatPro software was used to simulate phases present at different temperatures. Welding simulations using ANSYS evaluated residual stresses in the welds. The alloy with 43.499% Ni, 0.5% Al, 14% Co, 6% Mo, 10% Cu, 23% Fe, 2% Mn, 1
Microstructure and Abrasive Wear Properties of Chrome Alloy Steel IDES Editor
En 31 steel is widely used for applications like ball bearings and grinding media balls. The sliding wear properties of En 31 steel has been studied in the past, however the data on abrasive wear properties of En 31 steel is limited. En 31 steel was quenched and tempered at different tempering temperatures. Metallographic and hardness studies were carried out on heat treated samples. The hardened and tempered samples were tested using two body abrasive wear testing apparatus. The abrasive medium used in the present investigation was silicon carbide paper. The effect of normal load and sliding distance on wear loss of as received and heat treated specimens tempered at different tempering temperatures was investigated. The abrasive wear resistance of EN 31 steel with different hardness was compared under different test conditions. The worn out samples were observed by Scanning Electron Microscope to study morphology of worn surfaces. The abrasive wear resistance exhibited an increasing trend with increase in hardness and it was rationalized in terms of microstructure and the hardness.
Surface modification and properties modulation of r go film by short duration...Conference Papers
This document summarizes the effects of hydrogen (H2) and ammonia (NH3) plasma treatment on the surface properties and electrical conductivity of reduced graphene oxide (rGO) films. Short duration plasma treatment was performed at varying temperatures and plasma powers. Low-power H2 plasma induced further de-oxygenation of rGO and slightly reduced conductivity. NH3 plasma did not effectively dope the rGO with nitrogen but did induce defects, reducing conductivity. High-temperature NH3 plasma induced nitrogen doping and improved crystallinity but also significantly etched the rGO surface, greatly reducing conductivity. Electrical and optical properties of the rGO films were characterized through measurements of conductivity, Raman spectroscopy, and spectral ellipsometry to analyze
The document summarizes characteristics of Mo-47 wt.% Re alloy sheets produced by powder metallurgy. Microstructural analysis showed a two-phase precipitation structure. Hardness increased with deformation up to a thickness of 0.8 mm then stabilized, with some areas showing higher or lower hardness. TEM revealed sigma phases along grain boundaries in sheets with thickness of 0.27 mm. Tensile properties decreased with increasing temperature from room temperature to 1400 K.
International Journal of Engineering Research and DevelopmentIJERD Editor
The document studies the corrosion process of a Ni-Cr-Mo alloy used in dental prostheses. Electrochemical tests were conducted on samples of the alloy in NaCl solution, and the surface was analyzed at different points on the polarization curve. The results showed the alloy initially forms a protective oxide layer but undergoes transpassivation and intergranular corrosion at higher potentials, with preferential dissolution of regions lower in molybdenum.
Preparation and Structural Properties of Aluminium Substituted Lithium Nano F...IOSR Journals
This document describes the preparation and structural properties of aluminum-substituted lithium nanoferrites synthesized using the citrate gel auto combustion method. Nanoferrites with the general formula Li0.5AlxFe2.5-xO4 (where x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared at low temperature (1800C). X-ray diffraction analysis confirmed the formation of a single-phase cubic spinel structure with particle sizes ranging from 13 to 27 nm. Lattice parameter, density, and porosity were calculated from the XRD data and showed decreases with increasing aluminum content. Scanning electron microscopy revealed the formation of
The document summarizes the synthesis, characterization, and AC conductivity of nickel-doped magnesium ferrite. Key findings include:
1) Magnesium nickel ferrites were synthesized via a sol gel technique and sintered at 1473 K. X-ray diffraction analysis revealed the presence of a nickel oxide phase along with the ferrite phase, indicating an almost stoichiometric (Mg,Ni)-ferrite phase was obtained.
2) Scanning electron microscopy images showed the (MgNi) ferrite had a regular, granular structure with well-connected grains and an average grain size of 0.7 micrometers.
3) The AC conductivity of the magnesium nickel ferrite increased with increasing frequency
THERCAST: A new 3D simulation model for complete chaining casted and forged i...TRANSVALOR S.A.
This document presents a new 3D simulation model for casting and forging ingots. It combines casting and forging simulation modules to track defects from casting through forging operations. The model uses finite element analysis to simulate heat transfer, fluid flow, and mechanical behavior during solidification and forging. Simulation results can provide insight into defect formation during casting and how defects evolve during subsequent forging to help optimize process parameters and improve final product quality.
The document discusses the characterization and numerical optimization of chromium-free nickel alloy filler materials for dissimilar welding between stainless steel SS304. Eight alloys with compositions ranging from 40-43.5% Ni, 4-20% Mo, 0-16% Co, 10% Cu, 22-25% Fe, 0.5% Al, 1% Ti, and 0.001% C were analyzed. JMatPro software was used to simulate phases present at different temperatures. Welding simulations using ANSYS evaluated residual stresses in the welds. The alloy with 43.499% Ni, 0.5% Al, 14% Co, 6% Mo, 10% Cu, 23% Fe, 2% Mn, 1
Microstructure and Abrasive Wear Properties of Chrome Alloy Steel IDES Editor
En 31 steel is widely used for applications like ball bearings and grinding media balls. The sliding wear properties of En 31 steel has been studied in the past, however the data on abrasive wear properties of En 31 steel is limited. En 31 steel was quenched and tempered at different tempering temperatures. Metallographic and hardness studies were carried out on heat treated samples. The hardened and tempered samples were tested using two body abrasive wear testing apparatus. The abrasive medium used in the present investigation was silicon carbide paper. The effect of normal load and sliding distance on wear loss of as received and heat treated specimens tempered at different tempering temperatures was investigated. The abrasive wear resistance of EN 31 steel with different hardness was compared under different test conditions. The worn out samples were observed by Scanning Electron Microscope to study morphology of worn surfaces. The abrasive wear resistance exhibited an increasing trend with increase in hardness and it was rationalized in terms of microstructure and the hardness.
Surface modification and properties modulation of r go film by short duration...Conference Papers
This document summarizes the effects of hydrogen (H2) and ammonia (NH3) plasma treatment on the surface properties and electrical conductivity of reduced graphene oxide (rGO) films. Short duration plasma treatment was performed at varying temperatures and plasma powers. Low-power H2 plasma induced further de-oxygenation of rGO and slightly reduced conductivity. NH3 plasma did not effectively dope the rGO with nitrogen but did induce defects, reducing conductivity. High-temperature NH3 plasma induced nitrogen doping and improved crystallinity but also significantly etched the rGO surface, greatly reducing conductivity. Electrical and optical properties of the rGO films were characterized through measurements of conductivity, Raman spectroscopy, and spectral ellipsometry to analyze
The document summarizes characteristics of Mo-47 wt.% Re alloy sheets produced by powder metallurgy. Microstructural analysis showed a two-phase precipitation structure. Hardness increased with deformation up to a thickness of 0.8 mm then stabilized, with some areas showing higher or lower hardness. TEM revealed sigma phases along grain boundaries in sheets with thickness of 0.27 mm. Tensile properties decreased with increasing temperature from room temperature to 1400 K.
International Journal of Engineering Research and DevelopmentIJERD Editor
The document studies the corrosion process of a Ni-Cr-Mo alloy used in dental prostheses. Electrochemical tests were conducted on samples of the alloy in NaCl solution, and the surface was analyzed at different points on the polarization curve. The results showed the alloy initially forms a protective oxide layer but undergoes transpassivation and intergranular corrosion at higher potentials, with preferential dissolution of regions lower in molybdenum.
Preparation and Structural Properties of Aluminium Substituted Lithium Nano F...IOSR Journals
This document describes the preparation and structural properties of aluminum-substituted lithium nanoferrites synthesized using the citrate gel auto combustion method. Nanoferrites with the general formula Li0.5AlxFe2.5-xO4 (where x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared at low temperature (1800C). X-ray diffraction analysis confirmed the formation of a single-phase cubic spinel structure with particle sizes ranging from 13 to 27 nm. Lattice parameter, density, and porosity were calculated from the XRD data and showed decreases with increasing aluminum content. Scanning electron microscopy revealed the formation of
El documento describe las características de varios repositorios web digitales, incluyendo Box, Mega, Google Drive y Filezilla. Box ofrece 10 GB de almacenamiento gratuito y permite el intercambio seguro de archivos desde cualquier lugar. Mega ofrece 50 GB gratis y hasta 8 TB de ancho de banda al mes para cuentas pagadas. Google Drive proporciona 15 GB gratis y permite editar documentos en la nube desde cualquier dispositivo. Filezilla es un cliente FTP gratuito y de código abierto que es multiplataforma y admite protocolos
Attributional vs. Consequential Lifecycle Analysis of Transportation Fuelsjmdecicco
1. The document discusses the limitations of attributional lifecycle analysis (ALCA) models for regulating greenhouse gas emissions from fuels, as they do not fully account for consequential economic and market effects.
2. It argues for a two-track approach using verified facility-level carbon accounting to specify policy, and integrated assessment models informed by consequential LCA to help shape policy.
3. The goal is to move beyond the limitations of conventional LCA tools by reconstructing them to better represent complex dynamic systems and guide low-carbon fuel development.
El documento resume seis profecías Mayas sobre el fin del mundo en 2012. La primera profecía predice el fin del miedo y el materialismo el 22 de diciembre de 2012. La segunda profecía anuncia que el comportamiento humano cambiaría después de un eclipse solar en agosto de 1999. La tercera profecía predice un aumento de la temperatura global y cambios climáticos. La cuarta profecía señala que el derretimiento de los casquetes polares elevará el nivel del mar. La quinta profecía dice que los sistemas basados en
El documento critica severamente a la iglesia católica por varias prácticas que se desvían de las enseñanzas de la Biblia. Específicamente, señala que la iglesia católica ha cambiado la forma de celebrar la Santa Cena instituida por Jesús, negando a los feligreses beber del vino y usando una hostia en lugar de pan. También acusa a la iglesia católica de enseñar doctrinas falsas que llevan a las personas al infierno.
This summary provides an overview of Babun Samadder's curriculum vitae.
Babun is seeking a challenging position in information technology to further develop his technical skills. He has completed 10th and 12th grade and is currently in his third year pursuing a B.A. degree. His technical qualifications include training in computer hardware, networking, and Microsoft Windows Server 2008. He has experience assembling, installing, troubleshooting, and repairing computer hardware. His areas of networking interest include Cisco routers, switches, and Windows server administration. He is currently working as a technical support executive at Wishnet Pvt. Ltd. Babun lives in Halisahar, West Bengal, India and provides contact information.
José Adaury de la Cruz Germosen es un diseñador de escaparates y visual merchandising con experiencia en tiendas minoristas. Se graduó de la escuela de diseño Ártidi en Barcelona y ha trabajado en eventos y museos coordinando visuales y colocación de productos. Actualmente trabaja independientemente en proyectos de diseño de escaparates y showcases para tiendas.
Este documento presenta un caso clínico de una niña de 8 años que acude a consulta psicológica. Se recopilan datos generales de la niña y su familia, así como información sobre su desarrollo motor, verbal y de esfínteres. También se analizan aspectos de su funcionamiento escolar, familiar y emocional. Finalmente, se evalúan áreas como la sensorial, psicomotora, intelectual y emocional de la niña para identificar posibles conflictos.
Este documento introduce el concepto de potencial eléctrico. Explica que el potencial eléctrico es análogo al potencial gravitacional y mide la energía potencial eléctrica por unidad de carga. También define la diferencia de potencial como el trabajo requerido para mover una carga entre dos puntos, y explica que la energía potencial eléctrica depende solo de la posición de la carga.
Präsentation im Rahmen des Viertes Treffen des Arbeitskreises Wissenschaftliche Archive in Berlin,
"Übernahme und Bewertung von Forschungsdaten" am 09. März 2016 in der TU Berlin
Este documento describe la historia y proceso de elaboración del pimentón ahumado "La Chinata" de la empresa NETASA. Fundada en 1975 en Extremadura, España, la empresa ofrece el máximo control de calidad en su pimentón ahumado de pimientos cultivados y secados de forma tradicional en la región de La Vera. Actualmente es una marca reconocida a nivel nacional e internacional que exporta a más de 50 países.
La autoética se refiere a la ética para uno mismo y busca superar la "barbarie interior" mediante la cultura psíquica. Esto implica el autoexamen, la autocrítica y la práctica de la recursión ética para reconocer nuestro egocentrismo. Además, la autoética requiere desarrollar el altruismo y resistirse a la moralina y al sacrificio del prójimo. En última instancia, la autoética busca disciplinar el egocentrismo individual y fomentar la solidaridad con
Yoga is an ancient practice that can help manage stress through its physical postures and breathing exercises. It aims to unify the body and mind. The document outlines the eight limbs of yoga including ethical practices, physical postures, breathing, meditation, and achieving bliss. Several yoga poses are described that target areas of the body to reduce stress symptoms. The document advocates that healthcare providers can benefit from yoga to manage their own high stress levels from caring for patients. More research is still needed to understand the optimal types and duration of yoga for reducing stress and depression.
Cgap - banking on mobiles webinar - oct.01.2008jtraverso
The document discusses the emergence of branchless banking via mobile phones. It explores why branchless banking is gaining traction using existing retail infrastructure and technology. It outlines how to develop branchless banking channels like agent networks and mobile applications. It examines branchless banking models for different customer segments including low-income groups and assesses regulatory considerations.
Business in a [shoe string]- bicycle wheel. where is the business model pptCesar Malacon
In very few words how basic elements of business are organised. An analogy with the parts of a bicycle wheel.
for more please visit http://www.scribd.com/doc/74474599
SAP GRC online Training on Access Control , which includes all the four components Access Risk Analysis( ARA), Emergency Access Management ( EAM), Access Request Management(ARM), Business Role Management( BRM).
GRC 12 online training
SAP GRC 10 Online Training
DESIGN AND ANALYSIS OF STEAM TURBINE BLADE AND SHAFT ASSEMBLYIjripublishers Ijri
rotary motion. A system of angled and shaped blades arranged on a rotor through which steam is passed to generate
rotational energy. Moving fluid acts on the blades so that they move and impart rotational energy to the rotor.
The blades are designed in such a way to produce maximum rotational energy by directing the flow of the steam along
its surface. The blades are made at specific angles in order to incorporate the net flow of steam over it in its favour.
The blades may be of stationary or fixed and rotary or moving types, and shaft is designed to work in extreme conditions,
hear it has to bear the temperature which is coming from the steam and loads (weight and centrifugal force) of
the blades assembly and other assembly parts.
Structural Stability of Nano-Crystalline Aluminum-Glass CompositesIOSRJAP
Effects of particle size of the material in nanometer on solid state, structural properties AluminumGlass based samples are reported in this study. The particle size of 25µm was used for both Aluminum and Glass powders respectively. The samples were prepared in powdered form of various Al-Glass proportions. The weight of Aluminum ranges between 20 – 60 percent in the composites. Results showed from X-ray diffraction analyses that Aluminum addition and the determined particle size greatly influence the structural stability of the samples. It was revealed that samples were structurally stable in the range of Aluminum composition and the observed size of crystals, measured Width at Middle of Maximum Height and structural parameters were found in nanometers. The Al-Glass materials were noted to crystallize with FCC and BCC lattice structures.
IRJET- Effect of Trace Addition SB and NA in Al-Si AlloyIRJET Journal
This document summarizes research on modifying an Al-Si alloy by adding trace amounts of sodium (Na) and antimony (Sb). The researchers prepared Al-Si alloy samples with different weight compositions of Na and Sb added as modifiers. They analyzed the microstructure, hardness, and tensile strength of the modified alloys compared to an unmodified Al-Si alloy. Their results showed that higher Sb content and lower Na content led to finer eutectic silicon particles and improved mechanical properties. Specifically, a composition of 0.02% Na and 0.3% Sb produced the smallest and most uniformly distributed eutectic particles, enhancing the alloy's strength. In conclusion, modifying the Al-Si alloy with
El documento describe las características de varios repositorios web digitales, incluyendo Box, Mega, Google Drive y Filezilla. Box ofrece 10 GB de almacenamiento gratuito y permite el intercambio seguro de archivos desde cualquier lugar. Mega ofrece 50 GB gratis y hasta 8 TB de ancho de banda al mes para cuentas pagadas. Google Drive proporciona 15 GB gratis y permite editar documentos en la nube desde cualquier dispositivo. Filezilla es un cliente FTP gratuito y de código abierto que es multiplataforma y admite protocolos
Attributional vs. Consequential Lifecycle Analysis of Transportation Fuelsjmdecicco
1. The document discusses the limitations of attributional lifecycle analysis (ALCA) models for regulating greenhouse gas emissions from fuels, as they do not fully account for consequential economic and market effects.
2. It argues for a two-track approach using verified facility-level carbon accounting to specify policy, and integrated assessment models informed by consequential LCA to help shape policy.
3. The goal is to move beyond the limitations of conventional LCA tools by reconstructing them to better represent complex dynamic systems and guide low-carbon fuel development.
El documento resume seis profecías Mayas sobre el fin del mundo en 2012. La primera profecía predice el fin del miedo y el materialismo el 22 de diciembre de 2012. La segunda profecía anuncia que el comportamiento humano cambiaría después de un eclipse solar en agosto de 1999. La tercera profecía predice un aumento de la temperatura global y cambios climáticos. La cuarta profecía señala que el derretimiento de los casquetes polares elevará el nivel del mar. La quinta profecía dice que los sistemas basados en
El documento critica severamente a la iglesia católica por varias prácticas que se desvían de las enseñanzas de la Biblia. Específicamente, señala que la iglesia católica ha cambiado la forma de celebrar la Santa Cena instituida por Jesús, negando a los feligreses beber del vino y usando una hostia en lugar de pan. También acusa a la iglesia católica de enseñar doctrinas falsas que llevan a las personas al infierno.
This summary provides an overview of Babun Samadder's curriculum vitae.
Babun is seeking a challenging position in information technology to further develop his technical skills. He has completed 10th and 12th grade and is currently in his third year pursuing a B.A. degree. His technical qualifications include training in computer hardware, networking, and Microsoft Windows Server 2008. He has experience assembling, installing, troubleshooting, and repairing computer hardware. His areas of networking interest include Cisco routers, switches, and Windows server administration. He is currently working as a technical support executive at Wishnet Pvt. Ltd. Babun lives in Halisahar, West Bengal, India and provides contact information.
José Adaury de la Cruz Germosen es un diseñador de escaparates y visual merchandising con experiencia en tiendas minoristas. Se graduó de la escuela de diseño Ártidi en Barcelona y ha trabajado en eventos y museos coordinando visuales y colocación de productos. Actualmente trabaja independientemente en proyectos de diseño de escaparates y showcases para tiendas.
Este documento presenta un caso clínico de una niña de 8 años que acude a consulta psicológica. Se recopilan datos generales de la niña y su familia, así como información sobre su desarrollo motor, verbal y de esfínteres. También se analizan aspectos de su funcionamiento escolar, familiar y emocional. Finalmente, se evalúan áreas como la sensorial, psicomotora, intelectual y emocional de la niña para identificar posibles conflictos.
Este documento introduce el concepto de potencial eléctrico. Explica que el potencial eléctrico es análogo al potencial gravitacional y mide la energía potencial eléctrica por unidad de carga. También define la diferencia de potencial como el trabajo requerido para mover una carga entre dos puntos, y explica que la energía potencial eléctrica depende solo de la posición de la carga.
Präsentation im Rahmen des Viertes Treffen des Arbeitskreises Wissenschaftliche Archive in Berlin,
"Übernahme und Bewertung von Forschungsdaten" am 09. März 2016 in der TU Berlin
Este documento describe la historia y proceso de elaboración del pimentón ahumado "La Chinata" de la empresa NETASA. Fundada en 1975 en Extremadura, España, la empresa ofrece el máximo control de calidad en su pimentón ahumado de pimientos cultivados y secados de forma tradicional en la región de La Vera. Actualmente es una marca reconocida a nivel nacional e internacional que exporta a más de 50 países.
La autoética se refiere a la ética para uno mismo y busca superar la "barbarie interior" mediante la cultura psíquica. Esto implica el autoexamen, la autocrítica y la práctica de la recursión ética para reconocer nuestro egocentrismo. Además, la autoética requiere desarrollar el altruismo y resistirse a la moralina y al sacrificio del prójimo. En última instancia, la autoética busca disciplinar el egocentrismo individual y fomentar la solidaridad con
Yoga is an ancient practice that can help manage stress through its physical postures and breathing exercises. It aims to unify the body and mind. The document outlines the eight limbs of yoga including ethical practices, physical postures, breathing, meditation, and achieving bliss. Several yoga poses are described that target areas of the body to reduce stress symptoms. The document advocates that healthcare providers can benefit from yoga to manage their own high stress levels from caring for patients. More research is still needed to understand the optimal types and duration of yoga for reducing stress and depression.
Cgap - banking on mobiles webinar - oct.01.2008jtraverso
The document discusses the emergence of branchless banking via mobile phones. It explores why branchless banking is gaining traction using existing retail infrastructure and technology. It outlines how to develop branchless banking channels like agent networks and mobile applications. It examines branchless banking models for different customer segments including low-income groups and assesses regulatory considerations.
Business in a [shoe string]- bicycle wheel. where is the business model pptCesar Malacon
In very few words how basic elements of business are organised. An analogy with the parts of a bicycle wheel.
for more please visit http://www.scribd.com/doc/74474599
SAP GRC online Training on Access Control , which includes all the four components Access Risk Analysis( ARA), Emergency Access Management ( EAM), Access Request Management(ARM), Business Role Management( BRM).
GRC 12 online training
SAP GRC 10 Online Training
DESIGN AND ANALYSIS OF STEAM TURBINE BLADE AND SHAFT ASSEMBLYIjripublishers Ijri
rotary motion. A system of angled and shaped blades arranged on a rotor through which steam is passed to generate
rotational energy. Moving fluid acts on the blades so that they move and impart rotational energy to the rotor.
The blades are designed in such a way to produce maximum rotational energy by directing the flow of the steam along
its surface. The blades are made at specific angles in order to incorporate the net flow of steam over it in its favour.
The blades may be of stationary or fixed and rotary or moving types, and shaft is designed to work in extreme conditions,
hear it has to bear the temperature which is coming from the steam and loads (weight and centrifugal force) of
the blades assembly and other assembly parts.
Structural Stability of Nano-Crystalline Aluminum-Glass CompositesIOSRJAP
Effects of particle size of the material in nanometer on solid state, structural properties AluminumGlass based samples are reported in this study. The particle size of 25µm was used for both Aluminum and Glass powders respectively. The samples were prepared in powdered form of various Al-Glass proportions. The weight of Aluminum ranges between 20 – 60 percent in the composites. Results showed from X-ray diffraction analyses that Aluminum addition and the determined particle size greatly influence the structural stability of the samples. It was revealed that samples were structurally stable in the range of Aluminum composition and the observed size of crystals, measured Width at Middle of Maximum Height and structural parameters were found in nanometers. The Al-Glass materials were noted to crystallize with FCC and BCC lattice structures.
IRJET- Effect of Trace Addition SB and NA in Al-Si AlloyIRJET Journal
This document summarizes research on modifying an Al-Si alloy by adding trace amounts of sodium (Na) and antimony (Sb). The researchers prepared Al-Si alloy samples with different weight compositions of Na and Sb added as modifiers. They analyzed the microstructure, hardness, and tensile strength of the modified alloys compared to an unmodified Al-Si alloy. Their results showed that higher Sb content and lower Na content led to finer eutectic silicon particles and improved mechanical properties. Specifically, a composition of 0.02% Na and 0.3% Sb produced the smallest and most uniformly distributed eutectic particles, enhancing the alloy's strength. In conclusion, modifying the Al-Si alloy with
This document summarizes a study that characterized and numerically optimized eight different chromium-free nickel alloy filler materials for dissimilar welding of stainless steel SS304. The alloys were modeled using JMatPro software to predict phases and properties. Finite element modeling was used to simulate welding and predict residual stresses and distortion. The results showed maximum residual stress of 80 MPa and distortion of 0.325 mm for one alloy. Based on induced stresses, one alloy with composition 43.499Ni, 0.5Al, 14Co, 6Mo, 10Cu, 23Fe, 2Mn, 1Ti, 0.001C was determined to be most suitable as a filler material.
Microstructural and mechanical behaviour of zinc aluminium cast alloysIAEME Publication
The document summarizes a study on the microstructural and mechanical behavior of zinc-aluminum (ZA27) cast alloys with varying amounts of nickel (1-3% wt). Key findings include:
1) Increasing the nickel content resulted in higher tensile strength, yield strength, and hardness due to solid strengthening and formation of intermetallic phases along grain boundaries.
2) Ductility decreased with more nickel due to intermetallics acting as barriers to elongation.
3) Microstructural analysis revealed the presence of intermetallic compounds like AlNi3 and the formation of a metastable epsilon phase with increasing nickel content.
The document summarizes research on aluminum 7075 alloy composites reinforced with alumina nanoparticles. Microstructural analysis found that 1.0 wt% alumina nanoparticles provided the optimal properties. Specifically:
- 1.0 wt% alumina composites exhibited maximum hardness of 134 HV and lowest wear rate. Higher amounts resulted in decreased hardness and increased wear.
- SEM images showed alumina nanoparticles were well dispersed through the aluminum matrix. Some agglomeration was observed at higher nanoparticle fractions.
- XRD analysis confirmed the presence of aluminum and alumina phases. Peak broadening and shifts indicated refinement of aluminum grains with increased nanoparticles.
- AFM images showed increased surface roughness with higher nanoparticle content
Comparative Study on the High-Stress Abrasive Wear Behaviour of Zinc and Copp...IRJET Journal
This document presents a comparative study on the abrasive wear behavior of zinc-based and copper-based alloys. Pin-on-disc tests were conducted on samples of the two alloys under varying loads and sliding distances. The zinc-based alloy exhibited higher wear rates and friction coefficients than the copper-based alloy. Microstructural analysis found the zinc alloy had a dendritic structure with intermetallic phases, while the copper alloy contained copper and intermetallic compounds. Temperature and friction increased with load and sliding time for both alloys, with the zinc alloy experiencing higher temperatures and friction. The copper alloy showed better wear resistance overall.
Investigation on the Creep Behaviour of Friction Stir Processed Al Ni Composi...ijtsrd
Indentation creep experiments were carried out on friction stirred Aluminum Nickel composite. The samples were cut from Al Ni plate which was undergone by friction stir processing. The specimen was polished by different polishing methods to reveal the macro and micro structure of the material. The macro structure contains two zones base metal zone and friction stirred zone . Creep tests were carried out on both friction stirred and base metal region of test specimen at different temperatures with different loads. It was found that there was a significant difference between the creep rates of friction stirred region and that of base metal region when tested under various conditions. The Activation energy determined was found to in the range of 45KJ Mole to 55KJ Mole at lower temperatures. Based on these results it can be concluded that the operative mechanism is the dislocation creep. But at higher temperature the Activation energy was found to be in the range of 140KJ Mole to 170KJ Mole so the operative mechanism for creep is diffusion creep. Samples were metallographic ally prepared and the microstructures were studied under optical and scanning electron microscope. Results of the experiments were discussed. Marripally Ravikumar "Investigation on the Creep Behaviour of Friction Stir Processed Al-Ni Composite Material" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-1 , December 2020, URL: https://www.ijtsrd.com/papers/ijtsrd38145.pdf Paper URL : https://www.ijtsrd.com/engineering/mechanical-engineering/38145/investigation-on-the-creep-behaviour-of-friction-stir-processed-alni-composite-material/marripally-ravikumar
Modeling of very thin aluminum nitride film mechanical properties from nanoin...Javier García Molleja
This document summarizes a study that used nanoindentation to determine the mechanical properties, specifically the hardness and elastic modulus, of a very thin (250 nm) aluminum nitride film. Various models were applied and compared to account for the substrate influence at such low film thickness. For hardness, models by Jönsson and Hogmark, Korsunsky et al., and Puchi-Cabrera were selected. For elastic modulus, standard models using weight functions were not successful due to an "S-curve" variation with indentation depth, so the models were modified based on Avrami's law. The main results found the hardness to be 10 GPa and elastic modulus close to 150 GPa.
EXPERIMENTAL INVESTIGATION ON MECHANICAL TESTING OF AL7085/ALUMINA NANO COMPO...IRJET Journal
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superalloys, among several high temperature structural alloys, are the prime materials for numerous advanced
high temperature structural components. Several advanced processing technologies, such as isothermal forging,
equiangle extrusion, investment casting, directional solidification and single crystal technologies, similar and
dissimilar metal joining, destructive and non- destructive testing too have also evolved.
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microstructure and texture for ultra-thin sheet applications. Hence, a comprehensive study has been undertaken
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ageing.
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Liotti
1. A L L U M I N I O E L E G H E
Memorie
Study of the validity
of the Niyama criteria function
applied to the alloy AlSi7Mg
E. Liotti, B. Previtali
The presence of porosity in metallic components produced in foundry, is one of the most undesired
phenomena. It is now possible to predict the evolution and development of this event using modern
software to simulate solidification. This give the foundry industry enormous assistance and is an useful
tool for processes development.
Key words: aluminium and alloys, solidification, foundry
INTRODUCTION The objective of our investigation was to estimate the relia-
bility of the Niyama function in predicting the development
Research on this topic started at the beginning of the last of porosity in castings of the aluminium alloy AlSi7Mg.
century and the literature contains numerous and wide-ran-
ging articles. Since a precise description of these studies lies
outside the scope of this paper, we focus our attention on the EXPERIMENTAL METHODS
arguments most closely related to our work, and refer the
reader to more specific references and to the literature we The alloy used was AlSi7Mg, widely used in the foundry in-
have reviewed [5-54]. dustry and with well-known behaviour. Table 2 shows the
The research of Niyama et al. [51-52] is significant throu- nominal mechanical and thermal properties of this alloy,
ghout many of these studies, as shown by the frequent cita- and table 3 shows its chemical composition.
tions in a great number of works. Treating the phenomenon
in a simplified manner, Niyama correlated porosity to ther- UNI 3599 ; A356 ;
mal parameters and found that castings were sound only Denomination AlSi7Mg; G Al Si 7
over a certain limit value of his function.
The function is: Density (kg/m3) 2670
. Interval of solidification (°C) 620-559
N = Gs / √T
Thermal Conductivity (W/m°K) 138,171
where
Specific heat (J/kg) 963
N = value of Niyama function;
Gs= thermal gradient [°C/cm] ; Latent heat (J/kg) 389391
.
T = cooling rate [°C/s].
The function is very suitable for direct use with computers, Table 2 – Specifications of the alloy.
thanks to its simplicity and the limited parameters needed. Tabella 2 – Dati della lega.
This is surely contributes to its wide utilization. The limit
value of the function is dependent on the constants of the
material and of the system. Element Per cent value
Niyama conducted a great number of experiments on steel. It Si 6,50% - 7,50%
was demonstrated that the model works quite well on steel,
Cu 0,05% - 0,10%
but less well with different metals, in particular alloys with a
wide interval of solidification. The limit values proposed in Mg 0,25% - 0,45%
the literature for various metals are shown in table 1. Mn 0,40% - 0,60%
Fe 0,50% - 0,70%
Material Limit value Zn 0,05% - 0,10%
Ni 0,05% - 0,10%
Steel 1 Ti 0,10% - 0,20%
Cast Iron 0,75
Al alloys 0,25-0,30 Table 3 – Nominal chemical composition of the AlSi7Mg (%wt.).
Cu alloys 1,3 Tabella 3 – Composizione chimica della lega AlSi7Mg (%wt).
Table 1 – Limit value of the function of Niyama. The efficacy of the model was evaluated comparing the real
Tabella 1 – Valori limite della funzione di Niyama. porosity level, obtained in castings produced in foundry,
9/2006
with that which would be predicted by calculations using the
software programme.
Enzo Liotti, Barbara Previtali
We chose to study the behaviour of eight bars with cross
sections of varying dimensions.
Memoria vincitrice del premio Aldo Daccò 2004 We considered two thicknesses, four lengths and two sha-
pes of the section of the gating system.
la metallurgia italiana 33
2. A L L U M I N I O E L E G H E
Memorie
Fig. 3 – Visualization of the result through 2D image of the
criterion of Niyama for the specimen 15D-c.
Fig. 3 – Visualizzazione dei risultati attraverso un’immagine 2D
dei valori di Niyama per il provino 15D-c.
Fig. 1 – Specimen. Fig. 1 – Provino.
Thickness S Length L Running
Name (cm) (cm) system
10A-r 10 30,5 Rectangular
10A-c 10 30,5 Circular
10B-r 10 61 Rectangular
10B-c 10 61 Circular
15C-r 15 38 Rectangular
15C-c 15 38 Circular
15D-r 15 78 Rectangular
15D-c 15 78 Circular
Table 4 – Dimensions of the specimens. Fig. 4 – Simulation working, the entrance of the metal in the model.
Tabella 4 – Misure dei provini. Fig. 4 – Simulazione in corso, ingresso del metallo nel modello.
Figure 1 shows the samples; table 4 reports their characte- the samples and thus to locate the zones where the limit va-
ristics. lues were not exceeded. In these zones the presence of po-
The risers were put at one end of the bars and were desi- rosity was predicted.
gned using the Caine method [3]. Figure 3 illustrates the results for the sample 15D-c through
The ingates were put at the side of the riser, as shown in fi- a cut-plane plot, that shows data inside the casting in a 2D
gure 2. image.
We chose an unpressurized gating system with a gating ratio The data of the materials used were entered into the softwa-
of Ssprue/Singate=1/2 [1], [3]. re programme to run the simulations.
Three castings, with thermocouples inserted in the centreli-
Simulation ne of the bars and in the sand, were made to obtain experi-
The simulations were made with the commercial software mental data to verify and calibrate the software.
SOLID CAST created by “Finite Solution”. The program- In the simulations it was not necessary to draw the entire pou-
me, based on the finite difference method (FDM), calculates ring system; instead it was enough to insert the runner because
the equations of thermal transmission and shows outputs the software does not have a fluid dynamics modeller. Solid
such as thermal variables (thermal gradient, solidification ti- Cast has only a simplified simulation of the mold filling, based
me) or functions (Niyama), through 2D and 3D images. We on Bernoulli principle and conduction equation. Figure 4
utilized the programme to calculate the Niyama function in shows a simulation in process during the mould filling.
Fig. 2 – Rectangular (left) and
circular (right) section of the
running system.
Fig. 2 – Sistema di colata a
sezione rettangolare (sinistra)
e circolare (destra).
9/2006
34 la metallurgia italiana
3. A L L U M I N I O E L E G H E
Memorie
Experimental procedure Results and discussion
The castings were made using wood models, formed in sili- The castings were optically analyzed to evaluate the presen-
ca sand and resin, and then poured in gravity. ce of porosity. We chose a rectangular area of 50 mm2 in the
We used silica sand with grain fineness AFS 55-60 and centre of the bars as investigation zone. The micrographics
alkyd resin as binder. The parts in contact with the liquid were made at 25X. The samples were not chemically at-
metal were painted with a zircon water based varnish. We tacked. The porosity per cent level was estimated with an
did not put any type of filter in the feeding canals and the li- image analyser (Image ProPlus).
quid metal was not treated not outgas. In this way we gained some comparative values from the si-
The metal was melted in a gas furnace, allowed to rest, and mulations. The expected level of porosity was evaluated
poured at a temperature of 750°C. All castings were poured comparing the values of the Niyama function, calculated as
from the same bath. the average of four points taken near the investigation zone,
with the limit value. The presence of pores was expected in
the zones where the limit value was not exceeded.
At the end, the values of simulated porosity were compared
to real values.
Fig. 7 – Value of the function of Niyama (upper); relative area of
the pores in the specimens (lower).
Fig. 7 – Valori della funzione di Niyama (in alto); valori
percentuali della porosità nei provini (in basso).
Figure 7 shows the results of the study: the upper diagram
Fig. 5 – The moulds (upper), the eight specimens (lower). represents the calculated values of the Niyama function,
while the lower diagram shows the porosity level in each
Fig. 5 – Le motte (in alto), le otto fusioni (in basso). sample.
Observing the simulations we can see that pores developed
in the four longest castings: 10B-c, 10B-r, 15D-c, 15D-r.
The worst situations are those predicted in 10B-c/r, followed
by 15D-c/r, while in the other four porosity is not predicted.
Nearly no difference was found between castings with rec-
tangular or circular sections of the gating system.
From the real data it can be seen that the porosity level is
high only in 10B-c and 10B-r (superior to 15%). In all the
others it is lower, although not negligible. The most sound
samples are 15D-c/r followed by 10A-c/r and 15C-c/r. Mo-
reover, in the real situation, the rectangular running systems
are better than the others.
CONCLUSIONS
9/2006
The paper dealt with the study of the capacity of the Niyama
criterion in predicting porosity in aluminium foundry. The
Fig. 6 – The two types of gating system: rectangular (left) and predict values of Niyama criterion were compared with ex-
circular (right). perimental results, in terms of percentage porosity in the
Fig. 6 – Sistema di colata a sezione rettangolare(sinistra), cross section of the casting. The casting shape was quite ele-
circolare (destra). mental, consisting of a rectangular bar with different dimen-
la metallurgia italiana 35
4. A L L U M I N I O E L E G H E
sions and gate shape. In general a good agreement between [16] Paray, Clements, Kulunk, Gruzleski; In-situ temperatu-
Memorie
the Niyama criterion and the experimental results could be re measurement in low-pressure permanent-mold ca-
found, since the criterion individuates the best and worst sting; AFS transaction; 1997;
conditions. [17] Chiesa, Mammen; Use of solidification modeling of
However, the comparison shows some disagreement predict porosity distribution in Al A356 industrial ca-
between the predictions, based on the Niyama function, and stings; AFS transaction; 1998;
reality: [18] Dighe, Jiang, Tewari, Rahardjo, Gokhale; Quantitative
- the predictions underestimate the real values of the de- microstructural analysis of microporosity in cast A356
fects; aluminum alloy; AFS transaction; 1998;
- the differences between rectangular and circular feeding [19] Conley, Huang, Asada, Akiba; Experimental validation
systems were not predicted. of grain structure and microporosity simulation for
Like the other works present in literature, this experiment equiaxed Al A356 castings; AFS transaction; 1998;
confirms the limit of the model as applied to aluminium. [20] Magnusson, Arnberg; Method for measurement of fee-
One major limitation, also noted by other authors, is not to ding in Al alloys; AFS transaction; 1999;
consider the presence of gas in the liquid metal and not to [21] Chiesa, Regimbal; Distinguishing microporosity from
reproduce accurately the mould filling, which in the present macroshrinkage when modeling solidification of A356
work led to an incorrect prediction of porosity. castings; AFS transaction; 2001;
[22] Fergus, Setiawan; Hydrogen sensor for molten Alumi-
num; AFS transaction; 2001;
ACKNOWLEDGEMENTS [23] D.J.Diego J. Celentano; A thermomechanical model
with microstructure evolution for aluminium alloy ca-
The authors wish to thank the Fonderia Liotti (Ornavasso, sting processes; International Journal of Plasticity 18;
VB) for their help in carrying out experimental work for the 2002;
research presented in this article. [24] R.C. Atwood, P.D. Lee; Simulation of the three-dimen-
sional morphology of solidification porosity in an alu-
minium-silicon alloy; Acta materialia 51; 2003;
REFERENCES [25] M.A. Gafur, M. Nasrul Haque, K. Narayan Prabhu; Ef-
fect of chill thickness and superheat on casting/chill in-
[1] Carlo Panseri; Manuale di fonderia d’alluminio; Hoe- terfacial heat transfer during solidification of commer-
pli; 1966; cially pure aluminium; Journal of material processing
[2] Walter Nicodemi; Acciai e leghe non ferrose; Zanichel- technology; 2002;
li; 2000; [26] Atwood, Sridhar, Zhang, Lee; Diffusion-controlled
[3] Marco Santocchi, Francesco Giusti; Tecnologie mecca- growth of hydrogen pores in aluminium±silicon ca-
niche e studi di fabbricazione; Casa editrice ambrosia- stings: in situ observation and modelling; Acta materia-
na; 2000; lia 48; 1999;
[4] Kurz, Fische; Foundamentals of solidification; Trans [27] R.C. Atwood, S. Sridhar and P.D. Lee; Equation for nu-
Tech Publications; 1992; cleation of hydrogen gas pores during solidification of
[5] S.Viswanathan, H.D.Brody; Microporosity in Grain-re- aluminium seven weight percent alloy; Scripta materia-
fined Aluminum- 4.5% copper alloy and its relation to lia; 1999;
casting practice; AFS transaction, 1992; [28] Lee, Chirazi, Atwood, Wang; Multiscale modelling of
[6] V.K.Suri, H.Huang, J.T.Berry, J.L.Hill; Applycability solidification microstructures, including microsegrega-
of thermal parameter-based porosity criteria to long- tion and microporosity, in an Al–Si–Cu alloy; Material
freezing-range alluminum alloy; AFS transaction, science and engineering; 2003;
1992; [29] Lee, Chang, Chieu; Modeling of feeding behavior of
[7] Narayan-Prabhu, Madheswaran, Prasanna-Kumar, solidifying Al-7Si-0.3Mg alloy plate casting; Met.
Venkataraman; Computer modeling of heat flow and Trans. B; ago 1990;
microstructure fineness in chill-cast aluminium alloy [30] Piwonka e Flemings; Pore formation in solidification;
LM-24; AFS transaction, 1992; Trans. AIME; agosto 1966;
[8] Laurent, Rigaut; Experimental and numerical study of [31] Kubo e Pehlke; Matematical modeling of porosity for-
criteria functionsfor predecting microporosity in cast mation in solidification; Met. Trans. B; giugno 1985;
aluminium alloys; AFS transaction, 1992; [32] Lee, Chang, Chieu; The role of solidus velocity in the
[9] Emadi, Gruzleski; Effect of casting and melt variables feeding behavior of Al-7Si-0.3Mg alloy plate castings;
on porosity in directionally-solidified al-si alloys; AFS Mat. Sci. Eng.; 1990;
transaction, 1994; [33] Sigworth, Wang; Evolution of porosity in long-freezing
[10] A.M.Samuel, F.H.Samuel; Porosity factor in quality range alloys; Met. Trans.; 1993;
aluminum castings; AFS transaction, 1992; [34] Kurz, Giovanola, Trivedi; Theory of microstructural
[11] Tynelius, Major, Apelian; A parametric study of micro- development during rapid solidification; 1985;
porosity in the A356 casting alloy system; AFS transac- [35] Ransley, Neufeld; The solubility of hydrogen in liquid
tion, 1993; and solid aluminium; J. Inst. Met. ; 1948;
[12] Yeh, Jong, Hwang; Improved 3-D mold filling model [36] Pellini e Bishop; The contribution of the risers and chill
for complex castings and experimental verification; edge effects to soundness of cast steel plates, AFS
AFS transaction, 1993; Transactions; 1950;
[13] Sigworth, Wang, Huang, Berry; Porosity formation in [37] Pellini e Bishop; The contribution of the risers and chill
modified and unmodified Al-Si alloy castings; AFS edge effects to soundness of cast steel bars, AFS Tran-
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transaction; 1994; sactions; 1951;
[14] Kao, Chang; Feeding efficiency criteria for porosity [38] Deoras, Kondic; Testing the gas content of molten me-
formation in A356 alloy sand plate castings; AFS tran- tals in a foundry; Foundry trade J.; 1956;
saction; 1996; [39] Irani, Kondi; Casting and Mold design effects on sh-
[15] Chen, Hwang; Improvement on solidification modeling rinkage porosity of light alloys; AFS Transactions;
for A356.2 aluminum alloy; AFS transaction; 1996; 1969;
36 la metallurgia italiana
5. A L L U M I N I O E L E G H E
[40] Egler, Gockman; The behaviour of eutectic aluminium- mation in A356.2 castings; Pergamon Press; 1990;
Memorie
silicon alloys as regards solidification and the forma- [48] Chen, Engler; Hydrogen and porosity in aluminium si-
tion of shrinkage cavities; Aluminium; 1974; licon-magnesium alloys,part I: aluminium silicon al-
[41] Thomas, Gruzleski; An experimental study of the di- loys; Metall.; 1991;
stribution of microporosity in cast aluminium base al- [49] Walther, Adams, Taylor; Mechanism fore pore forma-
loys; British foundryman; 1978; tion in solidifying metals; AFS Transactions; 1956;
[42] Drossel; The influence of melt treatment on the density [50] Fredriksson, Svensson; On the mechanism of pore for-
of castings made from Al-Si cast alloys; Giessereitech- mation in metals; Met. Trans. B; 1976;
nik1981; [51] Niyama, Uchida, Morikawa, Saito; Predicting shrinka-
[43] Shahani; Effect of hydrogen on the shrinkage porosity ge in large steel castings from temperature gradient cal-
of aluminium copper and aluminium silicon alloys; culations; AFS International Cast Metals Journal; 1981;
Scan. J. of Metallurgy; 1985; [52] Niyama, Uchida, Morikawa, Saito; A method of sh-
[44] Iwahori; Behaviour of shrinkage defects and limited rinkage prediction and its application to steel casting
solid fraction of feeding on Al-Si alloys; AFS Transac- practice; AFS International Cast Metals Journal; 1982;
tions; 1985; [53] Ampuero, Charbon; Modeling of microporosity evolu-
[45] Argo, Gruzleski; Porosity in modified aluminium al- tion during the solidification of metallic alloys; TMS
loys; AFS Transactions; 1988; Conference proceedings on light metals; 1991;
[46] Fang, Granger; Porosity formation in modified and un- [54] Poirier, Yeum, Maples; A thermodynamic prediction
modified A356 alloy castings; AFS Transactions, 1989; for microporosity formation in aluminium rich Al-Cu
[47] Zou, Tynelius, Shivkumar, Apelian; Microporosity for- alloys; 1987.
A B S T R A C T
STUDIO SULLA VALIDITÀ DELLA FUNZIONE CRITERIO cessi di fonderia.
DI NIYAMA APPLICATA ALLA LEGA A356 Attraverso l’utilizzo di un software di simulazione della soli-
dificazione è stato ricavato il valore della funzione in esame
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Parole chiave: in una geometria prescelta e poi confrontato con i valori
alluminio e leghe, solidificazione, fonderia sperimentali ottenuti in fonderia. Dal confronto tra simula-
zioni e dati sperimentali è emerso che il modello di Niyama,
Con questo lavoro abbiamo voluto valutare l’efficacia del- nell’ambito del lavoro svolto, non è un’efficace indice di va-
la funzione criterio di Niyama nel predire lo sviluppo di po- lutazione dello sviluppo della porosità nella lega considera-
rosità durante la solidificazione nella lega AlSi7Mg in pro- ta.
la metallurgia italiana 37