524 Effect of volume fraction solid on microstructure and fluidity of AZ91D alloy on the new type semi-solid injection process

2007 ◽  
Vol 2007.15 (0) ◽  
pp. 359-360
Author(s):  
Kenji MIWA ◽  
Rudi S RACHMAT ◽  
Takuya TAMURA ◽  
Yasuji SAKAGUCHI
Keyword(s):  
Volume Fraction ◽  
Az91d Alloy ◽  
Injection Process ◽  
Fraction Solid ◽  
New Type ◽  
Semi Solid

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.

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.

Fluidity and Microstructures Characteristics of AZ 91D by Using New Type Semi-Solid Injection Process

2006 ◽  
Vol 116-117 ◽  
pp. 534-537 ◽  
Author(s):  
Rudi S. Rachmat ◽  
Takuya Tamura ◽  
Kenji Miwa
Keyword(s):  
Temperature Distribution ◽  
Solid Particles ◽  
Permanent Mold ◽  
Uniform Temperature ◽  
Injection Speed ◽  
Injection Process ◽  
Fraction Solid ◽  
New Type ◽  
Semi Solid ◽  
Fluidity Test

This research has been investigated fluidity and microstructures characteristics of AZ 91 D alloy using new type semi-solid injection machine. To ensure good casting products, uniform temperature distribution was required during heating in the injection cylinder of this machine. So, the injection cylinder was divided with six heating zones. Then temperature distribution in the injection cylinder was precisely controlled. AZ 91 D billets were heated to the desired temperatures in the injection cylinder, and injected into the permanent mold with injection speed about 430 mm/s. Fluidity was measured by using spiral permanent mold with the cavity of 1045 mm in length and 5 mm in thickness. The fluidity test has been done with the fraction solid from 0% - 60%. The fluidity was 905 to 153 mm for fraction solid 0% to 60%, respectively. At the fraction solid from 50% to 60% microstructures are consisted of spherical solid particles and the solid particles surrounded by liquid phase. The shape of solid particles begins to change at the fraction solid of 40%.

Effect of Solid Fraction on Microstructure and Casting Faults of AZ91D Alloys in New Type Semi-Solid Injection Process

2006 ◽  
Vol 116-117 ◽  
pp. 441-444 ◽  
Author(s):  
Kenji Miwa ◽  
Rudi S. Rachmat ◽  
Takuya Tamura
Keyword(s):  
Solid Fraction ◽  
Testing Machine ◽  
Solid Particles ◽  
Casting Defects ◽  
Permanent Mold ◽  
Forming Process ◽  
Injection Process ◽  
Controlling System ◽  
New Type ◽  
Semi Solid

We have developed new type semi-solid injection process, that is, runner-less injection process. In order to investigate the effects of solid fraction on microstructure and casting defects of AZ91D in new type semi solid injection process, semi-solid forming testing machine which has the same system as a runner-less injection machine has been made on an experimental basis. Its temperature controlling system has been established to obtain the homogeneous solid-liquid coexisted state in its injection cylinder. AZ91D billets are injected into a permanent mold by this machine in the semi-solid state. A shearing in the part of nozzle of injection cylinder is the most important to reveal thixotropic property of alloy slurry in semi solid forming process by injection machine. So it needs controlling of solid fraction to affect thixotropic property. In order to decrease casting defects and hold homogeneous structure, solid fraction more over 50% is needed. But when the solid fraction increases more than 50%, primary solid particles grow coarser, and then controlling method is required to suppress coarsening. In the case of less than 50% of solid fraction, liquid part preferentially fills inside the permanent mold and alloy slurry continue to fill the mold behind alloy liquid. Then large casting defects form at the boundary of both flows.

Effect of Holding Time on Microstructures of AZ91D Alloy by the Semi-Solid Thixo-Extruded Process

2015 ◽  
Vol 1088 ◽  
pp. 191-194
Author(s):  
Xiao Ping Zheng ◽  
Ze Sheng Ji ◽  
Wei Wen Zhang ◽  
Ming Shao
Keyword(s):  
Mechanical Property ◽  
Particle Size ◽  
Magnesium Alloy ◽  
Shape Factor ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Az91d Alloy ◽  
Az91d Magnesium Alloy ◽  
Semi Solid ◽  
The Relationship

The semi-solid thixo-extruded process of AZ91D magnesium alloy with 9 % plastic deformation was investigated. The effect of isothermal time on the thixo-extruded formability of AZ91D magnesium alloy was analyzed. The relationship between isothermal time and microstructure, mechanical property was also researched. The results showed that with increasing the isothermal time from zero to 60 min on 575 °C, the filling distance was increased firstly and then decreased, the solid volume fraction was decreased firstly and then increased, the tensile strength and elongation were also increased firstly and then decreased. However, the increasing isothermal time would lead to decrease of shape factor but the coarsening of particle size. When the isothermal time was 30 min, the solid volume fraction was lowest and the filling distance was greatly increased obviously.

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.

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