bluuebunny/crossref_metadata_2025 huggingface dataset:
In-Situ 3D Investigation by Fast X-Ray Microtomography of the Microstructural Changes Occurring during Partial Remelting of Al-Cu Alloys
Authors: Suéry Michel , Salvo Luc , Josserond Charles , Di Michiel Marco
Published: March 2009

The evolution of the microstructure of semi-solid Al-Cu alloys has been characterized
during isothermal treatments in the semi-solid state by using in-situ X-ray microtomography
experiments carried out at ESRF, Grenoble. This work is therefore a continuation of previous
experiments reported at the 8th S2P Conference in Limassol. Quantitative data are presented dealing
with changes with holding time of the solid volume fraction, of the solid-liquid interface area and of
the mean and Gaussian curvatures of the solid phase. Discussion of the results is carried out on the
basis of the mechanisms involved in semi-solid systems.
Effect of Isothermal Holding Temperature on Globularization of Primary Solid Phase in Multiplex-Type Slurry Cup
Authors: Kang Suk Won , Lee Dock Young , Kim Ki Bae
Published: March 2009

In order to produce a high quality and cost effective part in the rheocasting process for an
automobile industry it has been important to develop a slurry-on-demand process, which can
manufacture the semi-solid slurry having a fine and globular structure of primary solid phase. The
morphology of primary solid phase of semi-solid slurry is coarsened and globularized during an
isothermal holding process in a solid-liquid region. Accordingly, in this paper, the microstructural
evolution of semi-solid slurry during the isothermal holding at a various temperature in solid-liquid
region was investigated to examine a coarsening and globularization behavior of primary solid
phase. The semi-solid slurry of Al alloy was produced in a slurry maker using a multiplex-type
slurry cup that we developed recently. A size of primary solid phase was the finer at the higher
holding temperature, but under a constant holding time a roundness degree of primary solid phase
was the lower at the lower holding temperature. Also, a coarsening rate of primary solid phase was
not considered to be affected significantly by a holding temperature even though a little lower
coarsening rate was obtained at the higher holding temperature.
Optimization of Manufacturing Conditions of Semi-Solid Slurry in Multiplex-Type Slurry Cup
Authors: Kang Suk Won , Lee Dock Young , Kim Ki Bae
Published: March 2009

Recently, we have developed a slurry maker using a multiplex-type slurry cup for
rheoforming process. In the present study, the optimum manufacturing condition of semi-solid
slurry having a fine and globular structure of primary solid phase was investigated in the multiplextype
slurry cup. A various manufacturing condition, such as a pouring temperature of melt, a
preheating temperature of slurry cup, and a holding temperature and time of melt in slurry cup was
varied to make a processing map of the semi-solid slurry for rheoforming process. Through the
microstructural examination of primary solid phase of the interrupt-quenched semi-solid slurry of
Al-7wt%Si-0.35wt%Mg alloy produced in the multiplex-type slurry cup under a various
manufacturing condition, the optimum manufacturing condition of the semi-solid slurry for
rheoforming process were a pouring temperature of melt of 650, a preheating temperature of
slurry cup of 300, and an isothermal holding time of melt in slurry cup of 10min at 580.
Microstructural Evolution of AZ31 Mg Wrought Alloy during Partial Remelting for Thixoextrusion
Authors: Yoon Young Ok , Kim Shae K.
Published: March 2009

An attempt has been made to investigate feasibility of thixoextrusion for AZ31 Mg
wrought alloy through simple partial remelting. Microstructural evolution of AZ31 Mg wrought alloy
for thixoextrusion was investigated as functions of isothermal holding temperature and time in the
partially remelted semisolid state. The interesting point of this study was that the thixotropic
structures of AZ31 Mg wrought alloy without additional pretreatment could be obtained through
simple partial remelting. The uniform average grain size and liquid fraction according to the
isothermal holding time were very important for the thixoextrusion. Because, it is must be considered
on actual extrusion time. The liquid fraction was increased with increasing isothermal holding
temperature and time. But, the liquid fraction was almost uniform after 10 min. The average grain size
was decreased with increasing isothermal holding temperature. On the other hand, as the holding time
increased, the average grain sizes were uniform at 615 and 622. This phenomenon is very useful
for thixoextrusion in terms of process control such as actual extrusion time.
Dynamic Characteristics of the Sinter-Forged Cu-Cr Alloys with the Variation of Chrome Content
Authors: Song Jung Han , Huh Hoon
Published: March 2009

This paper is concerned with the dynamic characteristics of sinter-forged Cu–Cr alloy for
various strain-rates. The amount of the chrome content is varied from 10 %wt to 30 %wt in order to
investigate the influence of the chrome content on the dynamic characteristics. The dynamic response
at the corresponding level of strain-rate should be obtained with an adequate experimental technique
and corresponding apparatus due to the inertia effect and the stress wave propagation. In this paper,
the high speed tensile testing machine is utilized in order to identify the dynamic response of the
Cu–Cr alloy at the intermediate strain-rates and the split Hopkinson pressure bar is used at the high
strain-rates. Experimental results from both the quasi-static and the high strain-rates up to the 5000/s
are interpolated with respect to the amount of the chrome content in order to construct the
Johnson–Cook and the modified Johnson–Cook model as the constitutive relation for numerical
simulation of the dynamic impact behavior of electrodes.
Pressure-Composition-Isotherm Behavior of Partially Remelted Magnesium Alloys
Authors: Hong Tae Whan
Published: March 2009

Partially Remelted Mg alloys focused only to aspect of semi liquid forming until now. In
presents study, for the purpose of proposition as economic lightweight hydrogen absorbing materials,
the hydrogenation properties of pressure-composition-isotherm (PCI) apparatus. According to the
results of experiments, globules (Mg rich solid phase) were regarded the storage system as a hydrogen
absorption/desorption and eutectic/liquid droplets (quenched liquid phase) were considered the
catalytic system as an improving factor of hydrogenation kinetics. Especially, the hydrogenation
properties were depended on properties of globules and liquid fraction.
Fabrication of Rheological Material with Rotational Pressure Type Equipment
Authors: Seo P.K. , Kim Dae Up , Kang C.G.
Published: March 2009

Many rheocasting processes had been proposed because of the difficulty of recycling, the
limit of material, and the high cost of raw material in thixocasting. But, these rheocasting processes
also had disadvantages such as the high initial investment cost and the lower mechanical properties
than thixocasting. In this study, a continuous fabrication of rheological material with pressure rotation
equipment was newly devised to overcome the disadvantages of rheocasting process. In order to
investigate the thixoformability, reheating experiments were carried out with the material fabricated
by the newly devised equipment.
Effect of Disturbing Conditions in Semi-Solid State on Microstructure Evolution of Magnesium Alloy
Authors: Zhao Hong Jin , Kang Yong Lin , Wang Zhao Hui , Du Hai Liang
Published: March 2009

In this paper the microstructure evolution of AZ91HP magnesium alloy casts produced
under different disturbing treatment conditions such as non-disturbing, argon blowing and
mechanical stirring in semi-solid state after holding a short time was studied. The results show that
the grains of AZ91HP alloy casts refined, the secondary dendritic arms grown and the dendrites tend
to rosette shape with the decrease of holding temperature. External disturbance can accelerate the
evolution process, and the spherical primary α phase formed easily under mechanical stirring
treatment condition. The formation of non-dendritic structure is owing to ripening of the dendritic
arms, refinement of the grains and movement of the primary formed solid phases. Disturbing
treatments in semi-solid state induce more equilibrium solidification and decrease the amount of
brittle β-Mg17Al12 phase. Blowing argon into the refined and modified magnesium alloy in semi-solid
state can obtain homogeneous non-dendritic structure and the net shaped β phase distributed on α-Mg
phase boundaries become fine and thin, this may be have a good effect on the mechanical properties
of the magnesium alloy casts. Due to the low disturbing strength, argon blowing can maintain the
metallurgy quality of the semi-solid slurry well, and also have high efficiency to make it. This
technology need not new complex equipments and can be practiced in conventional casting
conditions, so it may be used in industrialize manufacture.
A Study on the Microstructural Defects in Slots of Thixoformed Copper Rotor
Authors: Lee Sang Yul , Lee Sang Yong
Published: March 2009

Cu-Ca alloys and the squirrel cage rotors for induction motors of small capacities were
used for the development of thixoforming processes. Processing conditions, motor efficiency and
forming defects in macro- and microscale for thixoforming of Cu-Ca rotors have been performed to
investigate the microstructural features and the filling phenomena in slots of squirrel cage rotor.
Inadequate filling due to the complexity of slot structure, separation of solidified metal from the slot,
porosities and phase inhomogenitites were typical microstructural defects found in thixoformed
Cu-Ca rotors. Exact flow control in terms of billet and die temperatures at slot gate especially, was
necessary to prevent significant defects such as incomplete filling of slot.
Mechanical and Adhesive Properties of Plasma CVD Coatings on Various Substrates Using Scratch Test
Authors: Ko Dae Cheol , Lee Jung Min , Kim Byung Min
Published: March 2009

In this paper, the adhesive properties of hard coatings(TiN, TiCN) made by plasma
chemical vapor depositions on non-nitrided and nitrided substrates was estimated using the scratch
test, where adhesion was measured by the critical load (Lc). This value was determined as the normal
force affecting the indenter and causing the coating detachment as well as the acoustic emission signal
containing the information on the extent of coating damage. Results of the test showed that harder
substrates and coatings give higher values of critical loads.
Sheet Formability of AA 1050 Al Alloy Sheet by Equal Channel Angular Pressing of Route C Type
Authors: Akramov Saidmurod , Kim In Soo , Lee Min Gu , Park Byung Hyun
Published: March 2009

Ultra-fine grained and high hardened Al sheet was obtained by Equal Channel Angular
Pressing (ECAP). During this process the microstructure, the hardness and the texture of AA 1050 Al
alloy sheet are changed by a severe shear deformation. The plastic strain ratio after the ECAP and
subsequent heat-treatment condition was investigated in this study. It was found that the average
r-value of the equal channel angular pressed and subsequent heat-treated specimen was 1.7 times
higher than that of the initial Al sheet. This could be attributed to the various texture formations
through the ECAP and subsequent heat-treatment of AA 1050 Aluminum alloy sheets.
An Experimental Study on the Oriented Mechanical Properties of Aluminum Micro Thin Foil Material
Authors: Lee Hye Jin , Lee Nak Kyu , Lee Hyoung Wook , Choi Seo Gou , Lee Geun An
Published: March 2009

This paper is concerned about the precision material property measurement of a micro
metal thin foil used in MEMS technology. Evaluations of reliability such as the life cycle endurance
test, impact test, and residual stress test are necessary for MEMS components, because MEMS
components require great precision and accuracy. However, in practical reliability tests, we should
consider various factors that make them hard to perform. In this manner, we use the analytical method
to evaluate the reliability of MEMS component rather than actual testing. In general, the analytical
method is utilized by software tools. Nevertheless, it is obviously necessary to acquire fundamental
properties of materials through real test methods. In this paper, we proposed the micro scale material
property measurement system to measure the oriented mechanical properties of aluminum thin foil.
Effect of Preheating Temperature of Multiplex-Type Slurry Cup on the Morphology of Primary Solid Phase of Semi-Solid Slurry
Authors: Kang Suk Won , Lee Dock Young , Kim Ki Bae
Published: March 2009

Semi-solid slurry for a rheocasting process requires a fine and globular structure of
primary solid phase. In the present study, in order to find an optimum preheating temperature of a
multiplex-type slurry cup in the slurry maker that we recently developed for the rheocasting process,
the semi-solid slurry was held for a various time of up to 60 min. in a multiplex-type slurry cup
preheated at a different temperature. A size and morphology of primary solid phase of the semisolid
slurry was measured and analyzed with the difference of the recorded cooling curve during the
solidification with respect to a preheating temperature of the slurry cup. Also, a microstructural
evolution and globularization mechanism occurred during the isothermal holding were discussed.
Finally, as considering the effect of a different casting condition on the morphology of primary solid
phase the optimum manufacturing condition of the semi-solid slurry for the rheocasting process was
proposed.
Semi Solid Casting and Forging of Steel
Authors: Hirt Gerhard , Bleck Wolfgang , Bührig-Polaczek Andreas , Shimahara H. , Püttgen Wolfgang , Afrath C.
Published: March 2009

The semi solid forming of steel has the potential of an innovative technology, which could
open a new possibility of metal components production. Earlier research works in the 1990s have
already shown the principal feasibility of the process but also revealed the various kinds of technical
problems. Since then, research works on steel processing have been continuously made in several
locations in Japan, USA and Europe. Currently, the focus of these research activities is the
development of suitable tool material and the achievement of high part quality, which is the key point
for the success of the process. This paper gives an overview of the previous research works and the
current state of the research with an outlook on future tasks for this challenge.
Fabrication, Microstructure and Mechanical Properties of a SiCw/ZK51A Mg Composite by Semi-Solid Extrusion Directly Following Liquid Infiltration
Authors: Hu Lian Xi , Yuan Yuan , Luo Shou Jing
Published: March 2009

A 20vol.%SiCw/ZK51A Mg-based composite was fabricated by the process of semi-solid
extrusion directly following liquid infiltration. The microstructure and mechanical properties of the
composite were investigated in comparison with its squeeze cast and hot extruded counterpart. The
results showed that, by semi-solid extrusion, the SiC whiskers were well aligned and microstructure
defects associated with the casting technology were eliminated. In addition, as compared with the
conventional hot extrusion, the damage to the SiC whiskers during semi-solid extrusion was
reduced significantly. Consequently, the composite fabricated by the semi-solid extrusion presented
the best whisker reinforcing effect, with its elastic modulus, 0.2% offset yield strength, and ultimate
tensile strength achieving 82.5GPa, 383.6MPa, and 431.8MPa respectively.
Development of Cup-Cast Method; Semi-Solid Slurry Preparation without External Stirring Force
Authors: Pahlevani Farshid , Endo Y. , Yaokawa J. , Itamura M. , Kikuchi M. , Nagasawa O. , Anzai Koichi
Published: March 2009

Semi-Solid metal (SSM) processing is now considered a commercially successful
manufacturing route producing millions of near net shape parts per annum for the automotive
industry. Although semi-solid process is currently widely used as a manufacturing process which
produces near net-shape metal component, the processes those used for the preparation of
semi-solid slurry still take a great deal of time, energy and money. Cup cast method – recently
developed by the authors – is able to make semi-solid slurry preparation as easy as pouring water
from a pitcher into drinking glass. In this method globular solid particles are prepared by controlling
the turbulence and heat distribution in the melt through pouring instead of applying certain external
stirring forces, in other common method. In the current study, cup cast method applied to Al-A356
alloy using simple cylinder. Vital factors of this method were optimized by investigating
micro-structures.
The MSCP Process for Semi-Solid Slurry Production
Authors: Tian Zhan Feng , Zhang Zhi Feng , Xu Jun , Shi Li Kai
Published: March 2009

Production of semi-solid slurry with fine and uniform microstructures is one of the basic
and key problems for the industrial application of semi-solid processing. The common disadvantages
of existing techniques are as follows: continuous production difficulty, high process controlling
requirement and low quality microstructure. In order to overcome those problems, the MSCP (Multielectromagnetic
Stirring Continuous Preparation) process has been developed by GRINM.
Experimental results show that annular chamber for feedstock production can improve the efficiency
of electromagnetic stirring and reduce the difficulty of temperature grad control. Compared with
single electromagnetic stirring, multi- electro magnetic stirring can achieve more uniform stirring.
Strict temperature grad control in annular chamber is the key of continuous preparation of high quality
semi-solid slurry. Semi-solid slurry of different solid fractions was obtained by MSCP.
Automated Semi-Solid Forging of Steel Components by Means of Thixojoining
Authors: Baadjou René , Shimahara H. , Hirt Gerhard
Published: March 2009

The thixoforming processes join the advantages of conventional forming technologies as
forging and casting in respect of the mechanical properties and the practicable geometries. Within the
framework of the Collaborative Research Centre 289 at the RWTH Aachen University intensive
investigations on semi-solid processing with some steel grades have been running. For this purpose an
automated thixoforging plant (thixo-cell) has been developed in a closed cooperation with several
industrial partners. With this equipment multi material demonstrator components have been
successfully produced by thixojoining using semi-solid X210CrW12 tool steel.
Application of the Continuous Rheoconversion Process (CRP) to Low Temperature HPDC-Part I: Microstructure
Authors: Pan Qin Yue , Wiesner Stuart , Apelian Diran
Published: March 2009

The continuous rheoconversion process (CRP) is a novel slurry-on-demand process that
was developed at MPI/WPI in 2002. The process is based on a passive liquid mixing technique in
which the nucleation and growth of the primary phase are controlled using a specially designed
“reactor”. The reactor provides heat extraction, copious nucleation, and forced convection during
the initial stage of solidification, thus leading to the formation of globular structures. This paper
presents our recent work on the scale-up of the CRP for industrial applications. Specifically, we
demonstrate an important application of the CRP to low temperature (low fraction solid) HPDC. In
Part I of this paper, we present salient results on microstructural characterization of CRP processed
castings vs. conventional die castings.
Research on the Composite Slurry Preparation and Rheocasting of Aluminum Alloy
Authors: Mao Wei Min , Bai Yue Long , Gao Song Fu , Tang Guo Xing
Published: March 2009

The study on new rheoforming technologies of semisolid alloys has recently been one
main subject interesting many professors, experts and industrials, and so many new methods about
preparing semisolid alloy slurry and rheoforming process have been put forward. The semisolid
slurry of AlSi7Mg alloy was prepared by being poured at a low superheat and stirred by an
electromagnetic field at a low power for a short time, and then the slurry was further soaked for
proper time and finally rheoformed into a key-shaped die cavity in this paper. The influence of
slurry temperature, injection specific pressure and injection speed on the rheoforming process was
also studied. The experimental results show that if AlSi7Mg alloy melt is poured at 630°C or 650°C
and meanwhile stirred by an electromagnetic field at a low power for a short time, the most primary
α-Al grains solidified in the slurry are spherical and only a few are rosette-like. If the slurry after
made is then soaked in the liquidus-solidus range for some time, the ripening of primary α-Al
grains is developed further and they become more spherical and larger. The experimental results
also show that the slurry temperature, injection pressure and speed have a great influence on filling
ability. The higher the slurry temperature, injection pressure and speed, the higher the slurry filling
ability, and the shorter the core distance from the ingate, the more easily the die cavity is filled.
With the given key-shaped casting, if only the slurry temperature should be equal to or more than
585,, or the injection pressure is equal to or more than 20 MPa, or the injection speed should be
equal to or more than 1.73m/s, the key-shaped die cavity can be filled completely. The
microstructural distribution in the casting is very homogeneous and it shows that the slurry prepared
by the new method is very suitable for rheoforming and helpful to obtaining high quality castings.
Effect of Roll Gap Geometry on the Evolution of Strain States and Textures during Asymmetrical Rolling in AA 1050
Authors: Huh Moo Young , Kang Hyung Gu , Kang C.K.
Published: March 2009

Asymmetrical rolling was performed by rolling AA 1050 sheets with different velocities of
upper and lower rolls. In order to study the effect of roll gap geometry on the evolution of strain states
and textures during asymmetrical rolling, the reduction per rolling pass was varied. After
asymmetrical rolling, the outer thickness layers depicted shear textures and the center thickness layers
displayed a random texture. With decreasing reduction per an asymmetrical rolling pass, the thickness
layers depicting shear textures increases. The strain states associated with asymmetrical rolling were
investigated by simulations with the finite element method (FEM).
Continuous Fabrication of Sound Semi-Solid Slurry for Rheoforming
Authors: Guo Hong Min , Yang Xiang Jie
Published: March 2009

An alternative method has been proposed for the continuous and sample production of
SSM slurry for the rheo-forming process. The process named “Low Superheat Pouring with a Shear
Field (LSPSF)” dose not use the conventional stirring process, instead, it uses solidification
conditions to control nucleation, nuclei survival and grain growth by means of low superheat
pouring, vigorous mixing and rapid cooling during the initial stage of solidification combined with
thereafter a much slower cooling. The method has been applied to A356, 201 and A380 Al-alloys.
The primary phases present in average equivalent diameter of 40-70μm, 35-50μm and 50-70μm for
A356, 201 and A380, respectively. The morphology of primary phases is nearly spherical with shape
factor of 0.78-0.86, 0.71-0.83 and 0.85-0.96 for A356, 201 and A380, respectively. For each of those
alloys, there is no eutectic entrapped within the primary phase. The advantages of the LSPSF include
process simplicity with high efficiency, easy incorporation into existing metal forming installation
without infrastructure changes and a wide process window for pouring temperature.
Parameter Estimation for Semi-Solid Aluminum Alloys Using Transient Experiments
Authors: Alexandrou Andreas N. , Georgiou Georgios C. , Tonmukayakul N. , Apelian Diran
Published: March 2009

A rotating vane-cup rheometer is used to determine the rheological properties of semi-solid slurries,
and a procedure is established for characterizing the rheology with emphasis given to the proper and
self-consistent evaluation of the material constants.
Evaluation of Strip Rolling Directly from the Semi-Solid State
Authors: de Pádua Lima Filho Antonio , Yamasaki Márcio Iuji
Published: March 2009

The aim of this work is to study the solidification conditions necessary to produce good quality/low
defect metal alloy strip when thixorolling directly from the semi-solid state. To facilitate the study
lead/tin alloys were chosen for their relatively low operating temperature. The objective is to
extrapolate these findings to the higher temperature aluminium alloys. Three alloys (70%Pb-
30%Sn, 60%Pb-40%Sn, 50%Pb-50%wtSn) were used particularly to study the influence of the
solidification interval. The equipment consists of a two roll mill arranged as an upper and lower
roller, where both rollers are driven at a controlled speed. The lower roller is fed with semi solid
alloy through a ceramic nozzle attached to the lower end of a cooling slope. Several types of nozzle
and their position at the roller were tested. This produced different solidifications and consequently
different finished strip. The alloys were first cast and then poured onto the cooling slope through a
tundish in order to create a continuous laminar flow of slurry and uniformity of metal strip quality.
The pouring was tested at different positions along the slope. The cooling slope was coated with
colloidal graphite to promote a smooth slurry flow and avoid the problem of adherence and
premature solidification. The metallic slurry not only cools along the slope but is also initially
super-cooled to a mush by the lower roller whilst at room temperatures, thus enabling thixorolling.
It was also found that the nozzle position could be adjusted to enable the upper roller to also
contribute to the solidification of the metallic slurry. However the rollers and the cooling slope
naturally heat up. Temperature distribution in these zones was analysed by means of three
thermocouples positioned along the cooling slope and a fourth in the base of the semi solid pool
within the nozzle. The objective being to design an optimum pouring and cooling system. The
formed strip was cooled down to room temperature with a shower of water. Microstructures of the
thixorolling process were analysed. The differences in solidification conditions resulted in differing
qualities of finished strip and corresponding defect types, all of which are a serious quality issue for
the rolled product.
Microstructure Evolution during Semi-Solid Processing of SCN-Water and Sn-Pb Alloys
Authors: Li Tao , Lin Xin , Huang Wei Dong
Published: March 2009

Microstructure evolution was investigated during the solidification of succinonitrile-5at.%
water transparent alloy and Sn–15 wt.%Pb alloy under mechanical stirring through in-situ observation
and quenching, separately. The results showed that the evolution of primary microstructures under
stirring experienced the growth of single grain particle and the successive agglomerating and
coarsening of multi-particles when the particle size reached a certain value. The increase of stirring
rate promoted the globular growth of solidification microstructure after it nucleated in the melt and
increase the grain size. Thus, the microstructure during semi-solid processing could be refined by a
controlled stirring and cooling process, which depended on the optimization among the stirring rate,
cooling rate and temperature at which the stirring rate is changed.
Rheology Forming Process of Cast Aluminum Alloys with Electromagnetic Applications
Authors: Kim T.W , Kang C.G. , Kang S.S.
Published: March 2009

This paper focuses on a rheo-forming of arm parts fabricated by an electromagnetic stirring
system (EMS). This forming process takes place under high pressure of high pressure die casting and
thin-walled casting is possible. Also, the productivity is higher than for low pressure die casting
because of the shorter cycle time. Rheo-forming is advantageous because forming is performed in the
semi-solid state with laminar flow and the gas content is low, which makes welding possible.
Therefore, this paper examines arm parts with EMS and has investigated the mechanical properties
after T6 and T5 heat-treatment.
Rheoforging of Steel
Authors: Knauf Frederik , Seidl I. , Hirt Gerhard
Published: March 2009

Rheoforging is a modification of semi-solid forging starting directly from the liquid phase
instead of reheating of a billet. In this process semi-solid slurry is prepared by pouring slightly
overheated melt over a slope into a holding cup to induce homogenous nucleation. By controlling the
casting temperature and holding time in the cup the desired semi-solid slurry with fine, globular
microstructure is successfully created. The inline forging trials using this slurry show the principal
feasibility of the process.
Influence of Slurry Temperature and Gate Velocity on Injection Molding of Magnesium Alloys
Authors: Ozaki Koichi , Tsuji Kazuya , Fukuta Tadao , Nomoto Takahito , Takeya Kengo , Hayakawa Teiji
Published: March 2009

In the present study, the influence of the slurry temperature and the gate velocity on the
apparent density of molded products was investigated using a thixomolding machine and a die having
a rectangular parallelepiped cavity. Magnesium alloy of AZ91D was injected into the cavity through a
rectangular gate. The gate velocity was varied from 0.4 m/s to 6.0 m/s and the slurry temperature was
changed between 853K and 903K, respectively. The die temperature was fixed at about 513K. The
results were as follows. The apparent density of the molded products at a constant gate velocity was
decreased gradually with an increase in the slurry temperature in cases the slurry temperature was
lower than 863K, however, it decreased suddenly at around the slurry temperature of 873K, and then
it took an almost constant value when the slurry temperature was over 873K. The apparent density of
the molded products at a constant slurry temperature was decreased greatly with an increase in the
gate velocity in the case the slurry temperature was over 873K, however, it decreases slowly as the
gate velocity increased for cases the slurry temperature was under 863K.
The SEED Technology for Semi-Solid Processing of Aluminum Alloys: A Metallurgical and Process Overview
Authors: Langlais Joseph , Lemieux Alain
Published: March 2009

As part of the foundry technology program, Alcan is developing a liquid-based slurrymaking
process known as the SEED technology for semi-solid forming. The technology is
presently entering the industrial and commercial stages, and will be used by the first customers in
late 2006. The semi-solid process offers many advantages to economically fabricate near-net-shape
parts having superior quality. The SEED process helps to overcome problems experienced with
thixocasting and especially the high cost of feedstock. The SEED process involves two main steps:
1) heat extraction to achieve a desired liquid/solid mixture, and 2) drainage of an excess liquid to
produce a self-supporting semi-solid slug that is formed under pressure. An overview of the
industrial SEED technology advantages such as the alloy processing flexibility (A356, AA6061)
and large slug dimensions and weights, is presented. The influence of the SEED processing
parameters (slurry preparation) on the final mechanical properties and the microstructure evolution
is also reported.
Potential of the Rheocasting Process, Demonstrated on Different Aluminum Based Alloy Systems
Authors: Grimmig T. , Ovcharov A. , Afrath C. , Bünck Matthias , Bührig-Polaczek Andreas
Published: March 2009

This work describes the processing of different aluminum cast- and wrought alloys in the
Cooling-Channel-Process. The investigations take the castability, the microstructural evolution for
the SSM-processing and the resulting properties in the test specimen into account. Beside the alloys
AlMg5Si2Mn (M59), AlCu4TiMgAg (AF48), AlSi12CuNiMg (SF70), AlSi17Cu4Mg (SF90),
AlZnMgCu1,5 (AA7075) the optimization of the alloy AlSi7Mg0,3 (A356) by the addition of
magnesium and copper were a main task of the work.
Mechanical and Microstructural Properties Investigation on Rheocast Automotive Parts Using A356 Alloy
Authors: Ma Chang Ik , Lee Ho Do , Kim Dae Up
Published: March 2009

Variations of cooling characteristics and solidification microstructure were investigated at
various melt pouring temperature, mold temperature and cooling condition for semi-solid slurry of
A356 alloy. And metallurgical and mechanical properties were examined with testing samples made
by rheocast process based on the obtained cooling conditions. Undercooled state of melt appeared
when superheating of melt was below 35, and it was easy to form equiaxed solidification structure.
Forced cooling hardly ever contributed to globular shaping of microstructure although it helped a
little to refine microstructure. And slow cooling through insulation and mold heating was effective to
form globular shape. Also, the metallurgical and mechanical properties of samples made by this
process were better than those of other sample made by conventional processes.
Semi-Solid Casting of Al-7wt%Si Alloy in Expendable Molds
Authors: Mirzadeh H. , NIROUMAND BEHZAD
Published: March 2009

Higher viscosities of semisolid metallic slurries have practically made their gravity
casting impossible and resulted in a need for some sort of mechanical force to push such viscous
slurries into die cavities. High pressure die casting has been conveniently used for this purpose.
However, due to high manufacturing cost of dies, only mass production of semisolid components
has been economically justified and practiced so far. In this work, as the first step for exploring the
possibility of production of semisolid cast components in expendable molds, fluidity of Al-7wt%Si
semisolid slurry in a centrifuging sand mold was examined. This paper reports the preliminary
results of the effects of solid fraction, applied force and section thickness on the fluidity of Al-7.1
wt%Si semisolid slurry in the sand mold.
Flow Characteristics of Thin Plate for Rheo-Diecasting Process in Commercial A356 Alloys
Authors: Sim J.G. , Moon J.Y. , Kim J.M. , Hong Chun Pyo
Published: March 2009

Effects of ingate velocities and the morphology of α-particles on feeding behavior of thin plate
were investigated in rheo-diecasting with H-NCM semisolid. In order to acquire various
morphological characteristics, three kinds of semisolid, which had different casting parameters, were
prepared. In this study, we found that the range of ingate velocity which could achieve laminar flow in
thin plate was from 3.88m/s to 6.47m/s. In this range, however, the laminar flow length and the total
flow length showed different results according to the characteristics of semisolid. Although the
semisolid had high globularity the semisolid which had larger α-particles than 100 showed
unstable feeding behavior in the range of stable ingate velocity.
Development of Aluminum-Lithium Alloys Processed by the Rheo Container Process
Authors: Sauermann Roger , Friedrich Bernd , Grimmig T. , Buenck M. , Bührig-Polaczek Andreas
Published: March 2009

This investigation describes the development and evaluation of thixoformable alloys on
Al-Li-Mg basis in the scope of the collaborative research center SFB 289 at RWTH Aachen
University. Scandium and zirconium was added to Al-Li2.1-Mg5.5 (A1420) with the aid of DoE
(Design of Experiments) and precursor billets were manufactured by pressure induction melting
(PIM). To evaluate the thixoformability of the synthesized alloys high-quality semi solid processed
demonstrators were manufactured by the Rheo-Container-Process. Subsequent heat treatment raised
the mechanical properties to maximum values of tensile strength of 432MPa, yield strength of
220MPa and an elongation of 13%. The RCP-Process was designed for the special requirements of
this high reactive alloy. The paper will present extraordinary benefits in terms of properties and
process simpleness for the semi-solid processing of Al-Li alloys.
Analysis of the Age-Hardening T5 Treatment in a Al-7%Si-0.6%Mg-0.5%Cu Rheo-Cast Alloy
Authors: Evangelista E. , Cabibbo Marcello , Spigarelli Stefano , Scalabroni C. , Balloni Luigi , Villa R. , Chiarmetta G.L.
Published: March 2009

The tensile properties and the microstructure of an Al-7%Si-0.6%Mg-0.5%Cu rheo-cast
component were investigated. The material underwent a T5 treatment, consisting in ageing at 160,
175 and 190°C for durations ranging from 0.5 to 48h. Tensile testing indicated that the T5 treatment
resulted in a relatively good level of strength and in a comparatively low ductility. In order to
improve ductility, maintaining as low as possible the cost of the final component, a single solution
treatment at 500°C for 4h was subsequently applied. The tensile strength and ductility of the
solution treated and aged material were higher than in the T5 condition. These differences were
attributed to the microstructural evolution occurring during exposure at 500°C, in particular to the
spheroidization of eutectic-Si and to a more homogeneous distribution of the precipitates.
The Effect of Stirring Current and Stirring Time on Microstructure and Mechanical Properties in Rheo Die Casting Process
Authors: Seo P.K. , Kang C.G. , Kim Byung Min
Published: March 2009

Semisolid processing is now becoming of greater interest for the production of various
parts than pressure die casting. In the rheo die casting process, the important thing is to control the
solid particles behavior during the rheo die casting process. So, in this paper, to find out the effect of
stirring current and stirring time on the microstructure and mechanical properties, rheo die casting
experiments were performed according to the stirring current such as 0, 20, 40 and 60 A and the
stirring time such as 20, 40 and 60 sec. The results to the experimental conditions were analyzed.
Fluidity and Microstructures Characteristics of AZ 91D by Using New Type Semi-Solid Injection Process
Authors: Rachmat Rudi S. , Tamura Takuya , Miwa Kenji
Published: March 2009

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%.
The Effect of Electromagnetic Stirring on the Semi-Solid Microstructure of High-Melting Alloys
Authors: Lim Sung Chul , Lee Heung Bok , Kim Kyung Hoon , Kwon Hyouk Chon
Published: March 2009

Most of the work reported at this conference concerned the semi-solid processing of low
melting point alloys, and in particular light alloys of aluminum and magnesium. It also can be true for
the higher melting point alloys, such as Cu alloys. The purpose of this paper is to develop a semi-solid
microstructure of Cu alloys using electromagnetic stirring applicable for squirrel cage rotor of
induction motor. The size of primary solid particle and the degree of sphericity as a function of the
variation in cooling rate, stirring speed, and holding time were observed. By applying electromagnetic
stirring, primary solid particles became finer and rounder relative to as-cast sample. As the input Hz
increased from 30Hz to 40Hz, particle size decreased. The size of primary solid particle was found to
be decreased with increasing cooling rate. Also, it decreased with stirring up to 3 minutes but
increased above that point. The degree of sphericity became closer to be 1 with hold time. Semi-solid
microstructure of Cu alloys, one of the high melting point alloys, could be controlled by
electromagnetic stirring.
Rheology and Rheometry of Aluminum Alloys: Influence of Shear and Vibration on Aluminum Flow Properties
Authors: Ouriev Boris
Published: March 2009

Understanding of flow properties and flow effects of liquid and semisolid aluminum
became a key solution for know-how of casting process. Therefore such properties must be
characterized a priory to layout of flow process parameters in order to predict structure formation of
aluminum in flow. In order to reach target of material characterization it becomes essential to
analyze materials under as close to real process conditions as possible. This task was solved by
strong modification of commercial rotational rheometer and application of high-resolution
temperature control. Besides understanding the flow properties it is essential to find the way of
interactive structure control during flow process. Therefore controllable effects were generated and
studied with the help of structure related rheological flow properties.
For triggering structure formation an influence of mechanical vibration on flow properties of highly
concentrated semisolid alloy is explored in this work. For that experimental set-up was designed
and adapted to conventional rotational rheometer with precise rheological characterization
capability. Priory to fundamental experiments with highly concentrated aluminum suspension a
number of calibration tests were performed. Also prediction of wall slippage in shear flow under
vibration was evaluated. Analysis of boundary conditions shows that no considerable side effects
were present during shear experiment under vibration.
The research reveals precise detection of transition temperatures with the help of steady and
transient shear viscosity measurement besides selective measurement of full rheological curves
within liquid and semisolid state temperature range. Rheological characterization was performed
under shear flow conditions with and without presence of orthogonal to flow direction mechanical
vibration. It was found that superposition of mechanical vibration and shear flow radically
decreases shear viscosity but only in semisolid state. Liquid state rheological properties shows
structural behavior but kept insensitive to application of mechanical vibration. For semisolid
alloys, comparison between reference shear viscosities at specified shear rates and those measured
under vibration shows considerable differences in flow properties. Conversion of concentrated
suspension from strongly shear-thinning to almost Newtonian flow behavior is reported here. It is
suggested to relate such phenomenon to non-equilibrium between structure formation and
disintegration under vibration and hydrodynamic forces of shear flow.
Influence of vibration on structure formation was also well observed during measurement of
solidification process. Comparison to reference data shows how sensitive structure of concentrated
suspension is to vibration in general and especially during solidification phase. The reveled effects
and observations provide a solid bases for further fundamental investigations of structure formation
regularities in flow of any highly concentrated systems.
Rheological Behaviour and Microstructural Evolution of Semi-Solid A356 Alloy Produced by Different Routes
Authors: Zoqui Eugênio José , Paes Marcelo , Robert Maria Helena
Published: March 2009

Different techniques used to produce semi-solid alloys can result in different structures in
the material and, therefore, in distinct rheological behaviours which determine its thixo-forming
ability. Suitable raw materials to be used for SSM forming must present non-dendritic, very fine or
fragmented structure in order to globularize without excessive agglomeration when re-heated to the
semi-solid state. This work analyses the influence of raw material production route on the
rheological behaviour of semi-solid A356 alloy. Techniques used were: electromagnetic stirring
(EMS) and chemical ultra-refining (UR). Samples were re-heated to 580oC (~ 0.45 solid fraction)
and hold for 0, 90 and 210s to allow the observation of the structure evolution. After structures
characterization, the samples were submitted to compression tests, at δH/δt = 10mm/s, in the same
temperature/holding time conditions. Viscosity of the differently prepared raw material was related
to the grain size, primary particle size, geometrical factor (roundness shape factor and contiguity).
Analytical Model for Heat Transfer Phenomena in Cup-Cast Method
Authors: Pahlevani Farshid , Yaokawa J. , Itamura M. , Kikuchi M. , Nagasawa O. , Anzai Koichi
Published: March 2009

Cup-cast method is a new method deals with semi-solid slurry preparation recently
developed by the authors. In this method, suspension of globular solid particles in molten metal is
prepared by controlling the nucleation and growth of solid-particles through the simplest and
quickest techniques. In this method, heat transfer phenomenon plays an important role in governing
the shape, size, and fraction of solid particles. In the current study, a heat transfer model was
proposed and applied to Al-A356 alloy semi-solid slurry preparation. The heat transfer model was
based on heat balance consideration between cup and slurry and it was in a good agreement with
experimental results.
Investigation on the Numerical Simulation for the Dynamic Transition from Liquid to Solid during Liquid-Solid Extruding Forming
Authors: Qi Le Hua , Zhou Ji Ming
Published: March 2009

The numerical simulation of liquid-solid extruding is completed with ABAQUS code in
this paper. The hydrostatic fluid element is used to simulate the deformation of liquid phase and the
continuum element is used to the solidified layer. The combination of fluid element and continuum
element avoids the mesh distortion of liquid phase during extruding. The dynamic transition from
liquid to solid is implemented by sequential coupled thermal-mechanical analysis. One illustrated
example of liquid-solid extruding is presented in this paper at last to show the whole modeling
process of the dynamic transition from liquid to solid in detail.