Control of Amount of α-Al Phase Particles in near Eutectic Al-Si Alloy by Electromagnetic Stirring

2022 ◽  
Vol 327 ◽  
pp. 250-254
Author(s):  
Yuichiro Murakami ◽  
Naoki Omura
Keyword(s):  
Solid State ◽  
Volume Fraction ◽  
Electromagnetic Stirring ◽  
Casting Alloy ◽  
Slow Cooling ◽  
Fraction Solid ◽  
Three Phase ◽  
Rotational Magnetic Field ◽  
Semi Solid ◽  
Si Content

Al-Si alloy is widely used as a casting alloy. The α-Al phase in the semi-solid state has low Si content in the Al-Si alloy. Then by separation of these α-Al phases from semi-solid Al-Si alloy, refining of aluminum can be possible. But, in near eutectic Al-Si alloy, few primary α-Al phases can be crystallized. If the fraction ratio of the α-Al phase can be increased, near eutectic Al-Si alloy can refine, and this method can be used for recycling. In this study, the effect of electromagnetic stirring (EMS) on the microstructure, especially the amount of the α-Al phase particles was investigated. A rotational magnetic field was applied to JIS ADC12 alloy which has near eutectic content during slow cooling from the liquid state to the solid-state, by using a three-phase AC coil. By applying EMS at solidification, the shape of the α-Al phase became particle shape from dendrite shape, and the amount of α-Al phase particles was increased. Moreover, by applying unidirectional intermittent EMS, the volume fraction of α-Al phase particles was decreased with increasing intermittent applying time. In ADC12 alloy, the primary α-Al phases can be crystallized only 10% generally, but it could be obtained over 40% by applying EMS. This means that the semi-solid slurry of near eutectic alloy with over 40% of fraction solid can be obtained by applying EMS.

Development of New Type Semi-Solid Injection Process for Magnesium Alloy

2014 ◽  
Vol 217-218 ◽  
pp. 361-365
Author(s):  
Yuichiro Murakami ◽  
Kenji Miwa ◽  
Naoki Omura ◽  
Shuji Tada
Keyword(s):  
Magnesium Alloy ◽  
Volume Fraction ◽  
Solid Particles ◽  
Casting Defects ◽  
Microstructure Observation ◽  
Injection Process ◽  
Fraction Solid ◽  
The Matrix ◽  
New Type ◽  
Semi Solid

We have developed new type semi-solid injection process for magnesium alloy. This process does not require to use any cover gases and the special magnesium billet such as thixo-billet. In this study, plate specimens were produced by injecting the semi-solid billet with different fraction solid. The microstructure observation, detection of casting defects by an X-ray computed tomography scanner, and tensile test were carried out. With increasing fraction solid, the size and shape of α-Mg solid particles became smaller and more spherical. In the condition of low fraction solid or forming in liquid state, the casting defects were located in the center of the specimen at the thickness direction. Additionally, the volume fraction of the casting defect decreased with increasing fraction solid. Moreover, the casting defects can be reduced by preventing solidifying and clogging of the top of the nozzle. Then, the specimen which has few casting defects could be obtained by injecting the slurry of fraction solid 0.5. However, the tensile strength and yield strength were highest in fraction solid 0.4. It is contemplated that the composition of the solid solution component element in the matrix was increased in fraction solid of 50%, therefore the matrix became brittle.

Microstructural Investigation of Semisolid Aluminum A356 Alloy Prepared by the Combination of Electromagnetic Stirring and Gas Induction

2019 ◽  
Vol 285 ◽  
pp. 290-295
Author(s):  
Nora Nafari ◽  
Farnoush Yekani ◽  
Hossein Aashuri
Keyword(s):  
Aspect Ratio ◽  
Shape Factor ◽  
A356 Alloy ◽  
Average Diameter ◽  
Electromagnetic Stirring ◽  
Microstructural Investigation ◽  
Porous Graphite ◽  
Three Phase ◽  
Semi Solid ◽  
Aluminum A356 Alloy

A three phase electromagnetic stirrer was used to agitate aluminum A356 slurry and a dry and oxygen free argon gas was introduced in to the slurry by a porous graphite core at a same time. The prepared semi-solid slurry was then transferred into a metallic mold and was compacted by a drop weight. Results demonstrated a favorable increase in shape factor, decrease in aspect ratio and average diameter size at different intensities of stirring. The intensity of stirring was changed by altering the current passed through the magnetic coil and also bubbling intensity via the porous graphite diffuser. Different time intervals for electromagnetic stirring and gas induction were applied. Agitating the slurry for 90 Sec. separately by electromagnetic stirrer and GISS method, gave better results in terms of shape factor, decrease in average diameter of the globules and aspect ratio.

Influence of Si and Mg Contents on the Mechanical Behavior of Al-Mg-Si Alloys in the Semi-Solid State under Isothermal and Non-Isothermal Conditions

2011 ◽  
Vol 690 ◽  
pp. 73-76
Author(s):  
Eliane Giraud ◽  
Michel Suéry ◽  
Michel Coret
Keyword(s):  
Solid State ◽  
Aluminum Alloys ◽  
Mechanical Behavior ◽  
Solid Fraction ◽  
Solid Alloy ◽  
Isothermal Conditions ◽  
Formation Of Cracks ◽  
Semi Solid ◽  
Si Content ◽  
Mg Content

The shear behavior of aluminum alloys containing increased amounts of Si or Mg compared with the 6061 alloy has been investigated by carrying out isothermal and non-isothermal tests in the mushy state during solidification. In isothermal conditions, it is shown that (i) an increase in Mg content leads to a more resistant semi-solid alloy compared with the 6061 alloy for the same solid fraction and (ii) an increase in Si content leads to a more brittle mushy alloy. In non-isothermal conditions, stress increases continuously with decreasing temperature with the formation of cracks for some compositions. This study shows that an increase in Mg content seems to be the most appropriate solution to reduce the formation of cracks in a solidifying 6061 alloy.

Effect of Volume Fraction Solid and Injection Speed on Mechanical Properties in New Type Semi-Solid Injection Process

2008 ◽  
Vol 141-143 ◽  
pp. 761-766 ◽  
Author(s):  
Naoki Omura ◽  
Yuichiro Murakami ◽  
Ming Jun Li ◽  
Takuya Tamura ◽  
Kenji Miwa
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Volume Fraction ◽  
Testing Machine ◽  
Permanent Mold ◽  
Injection Speed ◽  
Injection Process ◽  
Fraction Solid ◽  
New Type ◽  
Semi Solid

We have developed new type semi-solid injection process, that is, runner-less injection process which can obtain high material yield of about 90% for magnesium alloy. In this process, alloy billets are heated to the semi-solid temperature in the injection cylinder and are injected into a permanent mold. In order to investigate the effects of volume fraction solid and injection speed on microstructure and mechanical properties of AZ91D magnesium alloy injected into the permanent mold, semi-solid forming testing machine which has the same system as a runner-less injection machine, has been made on an experimental basis. The magnesium billet precisely controlled at given temperature has been injected into a permanent mold with two kinds (slow and high) of speed and plate-like specimens with each fraction solid have been fabricated. Microstructure has been observed by optical microscopy and X-ray computerized tomography (CT) scanner. Mechanical properties have been measured by tensile test. The effects of volume fraction solid of the alloy slurry and injection speed on mechanical properties have been clarified.

Thixoforming and Industrial Application of the Semi-Solid Alloy Al-6Si-2Mg

2006 ◽  
Vol 116-117 ◽  
pp. 72-75 ◽  
Author(s):  
Li Jun Xie ◽  
Jun Xu ◽  
Bi Cheng Yang ◽  
Zhi Feng Zhang ◽  
Li Kai Shi
Keyword(s):  
Heat Treatment ◽  
Continuous Caster ◽  
Die Casting ◽  
Electromagnetic Stirring ◽  
Solid Alloy ◽  
Fraction Solid ◽  
Casting Unit ◽  
Fine Microstructure ◽  
Automobile Components ◽  
Semi Solid

An application of the semi-solid alloy Al-6Si-2Mg to produce automobile components was carried out for farther development of this new alloy. The experiments were done in a self-developed SSM trial line composed of semi-continuous caster combined with electromagnetic stirring for feedstock billet production, 6-station induction reheating equipment for restoring thixotropy of SSM billet and modified die-casting unit for semi-solid thixoforming. The results show that Al-6Si-2Mg alloy has such a suitable fraction solid and low temperature sensitivity of fraction solid that the controllability of SSM process is increased greatly. The billets have uniformly fine microstructure with a higher degree of sphericity and also retain good thixotropic properties. During thixoforming, the die is filled completely, the microstructure of components is dense, and the primary phases are near spherical, and the mechanical property after heat treatment has good performance.

scholarly journals Application of Artificial Intelligence and Gamma Attenuation Techniques for Predicting Gas–Oil–Water Volume Fraction in Annular Regime of Three-Phase Flow Independent of Oil Pipeline’s Scale Layer

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1460
Author(s):  
Abdulaziz S. Alkabaa ◽  
Ehsan Nazemi ◽  
Osman Taylan ◽  
El Mostafa Kalmoun
Keyword(s):  
Gamma Radiation ◽  
Volume Fraction ◽  
Phase Flow ◽  
Gas Oil ◽  
Oil Pipeline ◽  
Intelligent Technique ◽  
Scale Layer ◽  
Three Phase ◽  
Three Phase Flow ◽  
Annular Regime

To the best knowledge of the authors, in former studies in the field of measuring volume fraction of gas, oil, and water components in a three-phase flow using gamma radiation technique, the existence of a scale layer has not been considered. The formed scale layer usually has a higher density in comparison to the fluid flow inside the oil pipeline, which can lead to high photon attenuation and, consequently, reduce the measuring precision of three-phase flow meter. The purpose of this study is to present an intelligent gamma radiation-based, nondestructive technique with the ability to measure volume fraction of gas, oil, and water components in the annular regime of a three-phase flow independent of the scale layer. Since, in this problem, there are several unknown parameters, such as gas, oil, and water components with different amounts and densities and scale layers with different thicknesses, it is not possible to measure the volume fraction using a conventional gamma radiation system. In this study, a system including a 241Am-133Ba dual energy source and two transmission detectors was used. The first detector was located diametrically in front of the source. For the second detector, at first, a sensitivity investigation was conducted in order to find the optimum position. The four extracted signals in both detectors (counts under photo peaks of both detectors) were used as inputs of neural network, and volume fractions of gas and oil components were utilized as the outputs. Using the proposed intelligent technique, volume fraction of each component was predicted independent of the barium sulfate scale layer, with a maximum MAE error of 3.66%.

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