Rheological Behavior and Fluidity of Semi-Solid SiCp/A357 Composites with Different SiC Addition Levels

2016 ◽  
Vol 256 ◽  
pp. 126-132 ◽  
Author(s):  
Zhen Lin Zhang ◽  
Zhi Feng Zhang ◽  
Jun Xu ◽  
Wei Min Mao
Keyword(s):  
Shear Rate ◽  
Solid Fraction ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Stir Casting ◽  
Sic Particles ◽  
Semi Solid ◽  
Test Casting ◽  
Good Agreement

The apparent viscosities of the semi-solid SiCp/A357 composites with 0vol.%, 10vol.% and 20vol.% SiC particles manufactured by stir casting were investigated using a Couette type viscometer, and the composite fluidity was examined with a test casting. The results showed that, the viscosities of the semi-solid SiCp/A357 composites decreased with an increase in shear rate, but increased with the increasing of solid fraction, and apparent viscosity of 10vol.% SiCp/A357 composite was the lower than that of 20vol.% SiCp/A357 composite at the same solid fraction; and the composite fluidity results were in a good agreement with the viscosity ones.

The Rheological Behavior of HS6-5-2 Tool Steel for Non-Isothermal Processing

2012 ◽  
Vol 192-193 ◽  
pp. 317-322
Author(s):  
Farzad Hosseini Yekta ◽  
S.A. Sadough ◽  
Vahid Pouyafar ◽  
Amin Jabbari
Keyword(s):  
Shear Rate ◽  
Cooling Rate ◽  
Tool Steel ◽  
Solid Fraction ◽  
Rheological Behavior ◽  
Liquid Fraction ◽  
Outer Cylinder ◽  
Processing Temperature ◽  
Applied Torque ◽  
Semi Solid

The rheological behavior of semi-solid tool steel is investigated using a conventional rheometer under cooling rate and shear rate. The processing of steels in semi-solid state is still at development stage due to the high processing temperature involved. The candidate grades of steel for thixoforming are high speed, high carbon, stainless steel and ductile iron. TheHS6-5-2 tool steel has a wide semi-solid range of over 200 C and the required spheroidal microstructure achieved by partial re-melting from as supplied state without any mechanical agitation, indicated the potential of this grade to be investigated in semi-solid processing. For non-isothermal processing an increase of solid fraction related to solidification due to thermal exchanges is observed. In the first series of experiment after melting the feed stock in an alumina cup, the alloy is sheared continuously by a rotating rod with a constant shear rate under three different cooling rates to the 55% corresponding liquid fraction. In the second series of experiment three different shear rates were applied under a constant cooling rate. The apparent viscosity of the slurry as a function of cooling rate and solid fraction is calculated from the applied torque to the outer cylinder. The results show that the slurry viscosity decreases with increasing shear rate and increases with increasing cooling rate and solid fraction. Additionally for a given solid fraction, shear thinning behavior is observed.

Apparent Viscosity and Rheological Behavior of Aluminum-Alloy Slurry Containing Nano-Sized SiC Particles

2019 ◽  
Vol 285 ◽  
pp. 391-397
Author(s):  
Kang Lu ◽  
Shu Sen Wu ◽  
Shu Lin Lü ◽  
Chong Lin
Keyword(s):  
Aluminum Alloy ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Mass Fraction ◽  
Matrix Alloy ◽  
Rotating Cylinder ◽  
Viscous Force ◽  
Semi Solid ◽  
The Relationship ◽  
Cylinder Viscometer

The apparent viscosity and rheological behavior of nanoSiCP/Al-5Cu composites were studied by using a high temperature coaxial rotating cylinder viscometer. The results show that mass fraction of nanoSiCP is an important factor for apparent viscosity of the nanoSiCP/Al-5Cu composites, and there is a great enhancement of apparent viscosity of the slurry with the increase of nanoSiCp content. It can attribute to the viscous force between nanoSiCp and matrix alloy melt above the liquidus. The increased amplitude of apparent viscosity in semi-solid state is far less than those in liquid state with the increase of mass fraction of nanoSiCp. The apparent viscosities of the composites reinforced with 0.5%, 1%, 1.5% and 2% nanoSiCp at 700°C were 24.78%, 95.25%, 160.29% and 228.62% higher than that of Al-5Cu alloy, respectively. Besides, the rheological model of nanoSiCP/Al-5Cu composites was established based on the fitting curve, which can precisely describe the relationship between the apparent viscosity of nanocomposites slurry and nanoSiCp mass fraction.

Influence of Morphology on the Rheological Behavior of Semi-Solid A356 Aluminum Alloy

2006 ◽  
Vol 116-117 ◽  
pp. 601-605
Author(s):  
Heng Hua Zhang ◽  
Xian Nian Zhang ◽  
Guang Jie Shao ◽  
Luo Ping Xu ◽  
Yi Tao Yang ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
A356 Alloy ◽  
Solid Alloy ◽  
A356 Aluminum Alloy ◽  
A356 Aluminum ◽  
Semi Solid

The morphology of semi-solid alloy is one of the key influence factors on the rheological behavior of slurry during die filling and the mechanical properties of formed parts. However, it is difficult to study such effect due to hard controlling of morphology in semi-solid state. In this paper, a self-developed Searle-type viscometer was used to determine the rheological behavior of A356 aluminum alloy in different morphology, which was refined with the salts mixture of K2TiF6 and KBF4. The results indicated that the flow behavior of refined A356 alloy in the semi-solid state possesses obviously thixotropic behavior under isothermal shearing condition with less time to reach steady state and lower steady apparent viscosity as compared to that of the A356 alloy. During continuous cooling at a constant shearing rate, the apparent viscosity of refined A356 slurry in the same solid fraction decreased with the content of Ti. It is shown from quantitative image analysis that the primary α-Al grain in the refined alloy evolves from dendrites to rosettes or sphericitys, and then tends to be rounder and finer in higher Ti content. The mechanism of the influence of morphology on rheological behavior was also discussed in this paper.

The Steady State Rheological Behavior of Semisolid AlSi6Mg2 Alloy

2011 ◽  
Vol 339 ◽  
pp. 257-260 ◽  
Author(s):  
Hong Chao Luo ◽  
Shi Pu Chen ◽  
Qin Nie ◽  
En Sheng Xu ◽  
Li Ping Ju
Keyword(s):  
Steady State ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Solid Particles ◽  
Experimental Results ◽  
Present System ◽  
Flow Conditions ◽  
Good Agreement

In the present work, basing on the rheological model of Chen and Fan (CF) [1] of semisolid metal slurries (SSMS), the rheological behavior at steady state of AlSi6Mg2 alloy is investigated. Experimental results on steady state viscosity of the present system in the literature are used to determine the parameters of the CF model by fitting. It has been shown that the steady state viscosity and the average agglomerate size increase with increasing the solid volume fraction and decreasing the shear rate. The theoretical prediction of the CF model is in good agreement with the experimental results in the literatures quantitatively. The importance of the effective solid volume fraction is shown by explaining the strong coupling between the viscosity and the microstructure. Specifically, the external flow conditions such as shear rate influences the viscosity by changing the agglomeration degree of the solid particles, that is, the effective solid volume fraction and then changing the viscosity.

Numerical Analysis of Semi-Solid Die-Casting Automobile Part Based on the Thermo-Visco-Plastic Constitutive Relation

2015 ◽  
Vol 1096 ◽  
pp. 268-274 ◽  
Author(s):  
Jiao Jiao Wang ◽  
Gui Min Lu ◽  
Jian Guo Yu
Keyword(s):  
Shear Rate ◽  
Aluminum Alloys ◽  
Apparent Viscosity ◽  
Volume Fraction ◽  
Die Casting ◽  
Solid Volume Fraction ◽  
Casting Process ◽  
Processing Parameters ◽  
Compression Tests ◽  
Semi Solid

Thermal simulation compression tests were performed on semi-solid billet in order to observe and investigate the behavior of 6061 aluminum alloys while varying the processing parameters such as apparent viscosity, the shear rate and the temperature. Specimens of 6061 aluminum alloys were characterized with their semi-solid behavior during partial melting and holding in the semi-solid state. Furthermore, the constitutive equation of semi-solid 6061 aluminum alloys was investigated. Moreover, the tests allow the apparent viscosity and shear rate of the alloys to be determined as a function of the solid volume fraction and strain rate together with the geometry behavior of the specimen. Utilizing these parameters, semi-solid die casting process of 6061 aluminum alloys could be simulated by the change of the solid volume fractions.

scholarly journals Rheological Properties of Polysaccharides from Longan (Dimocarpus longanLour.) Fruit

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Xingxun Liu ◽  
Yongyue Luo ◽  
Chunjie Zha ◽  
Sumei Zhou ◽  
Liya Liu ◽  
...  
Keyword(s):  
Shear Rate ◽  
Chemical Analysis ◽  
Rheological Properties ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Small Amplitude ◽  
Flow Behavior ◽  
Viscoelastic Behavior ◽  
Dynamic Shear ◽  
Small Amplitude Oscillatory Shear

Longan polysaccharide (LP) was extracted from longan (Dimocarpus longanLour.) pulp. The composition and rheological properties were determined by chemical analysis and dynamic shear rheometer. The flow behavior and viscoelastic behavior of longan polysaccharide (LP) solution were investigated by steady shear and small amplitude oscillatory shear (SAOS) experiments, respectively. The result shows that the solution is a pseudoplastic flow in a range of shear rate (1–100 s−1). The rheological behavior of LP was influenced by cations such as Na+and Ca2+. With an increase of apparent viscosity,G′andG′′were accompanied by addition of Na+and Ca2+.

scholarly journals CHROMATOGRAPHIC, RHEOLOGICAL AND CYTOCHEMISTRY EVALUATION OF “BACURI” PULP (Platonia insignis MART.)

2014 ◽  
Vol 32 (1) ◽  
Author(s):  
ANDRÉA CARDOSO DE AQUINO ◽  
CÍCERO DE SOUZA LIMA ◽  
FILIPE XAVIER FEITOSA ◽  
MARIA IZABEL GALLÃO ◽  
GUSTAVO ADOLFO SAAVEDRA PINTO ◽  
...  
Keyword(s):  
Shear Rate ◽  
Rheological Behavior ◽  
Physicochemical Characterization ◽  
Effect Of Temperature ◽  
Rheological Measurements ◽  
Cytochemical Analysis ◽  
Linalool Oxide ◽  
Increasing Temperature ◽  
Good Agreement ◽  
Newtonian Behavior

“Bacuri” pulp was evaluated for volatile compounds, rheological behavior, and cytochemical analysis. The pulp was also submitted to physicochemical characterization. The effect of temperature on rheological behavior of whole “bacuri” pulp was investigated in this work. The rheological measurements were carried out using a Brookfield Rheometer (Model DV-II +) at shear rate range from 0.25 to 1.50 s-1 at temperatures of 30, 40, 50, 60 and 70 °C. A total of 36 compounds were detected in the headspace of the “bacuri” pulp - 34 of which were identified. The major compounds were the following: linalool, cis-linalool, trans-linalool oxide, and hotrienol, respectively. The experimental data was adjusted using a power law rheological model, with good agreement. “Bacuri” pulp shows a non-Newtonian behavior, with an apparent viscosity decreasing with increasing temperature. The “bacuri” pulp obtained activation energy at shear rate 1.50 s-1 was -14.03 kJ/mol.

Study on Thixotropic Property of A356 Alloy in Semi-Solid State

2012 ◽  
Vol 192-193 ◽  
pp. 335-340 ◽  
Author(s):  
Sudip Simlandi ◽  
Nilkanta Barman ◽  
Himadri Chattaopadhyay
Keyword(s):  
Shear Rate ◽  
Flow Field ◽  
Apparent Viscosity ◽  
Sudden Change ◽  
A356 Alloy ◽  
Momentum Conservation ◽  
Structural Parameter ◽  
Parallel Plates ◽  
Transient Nature ◽  
Semi Solid

In the present work, the thixotropic property of a semisolid aluminium alloy (A356) under deformation is investigated numerically where the Couette flow between two parallel plates is considered. The flow field is represented by momentum conservation equations where the non-Newtonian behavior of the semisolid material is represented by the Herschel-Bulkley model. The agglomeration and the de-agglomeration phenomena of the suspended particles under shear are represented using a time dependent structural parameter influenced by the rate of strain and shear stress. The simulation predicts the flow field, rate of strain and apparent viscosity of the semisolid materials under transient and steady state conditions. It is found that the apparent viscosity shows a transient nature during sudden change in the shear rate, and its value decreases with increasing shear rate and vice-versa. It is also found that the present prediction shows a good agreement with prior work.

scholarly journals Rheology of Sesame Pastes with Different Amounts of Water Added

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Li-Xia Hou
Keyword(s):  
Shear Rate ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Water Type ◽  
Water Addition ◽  
Quality Of Water ◽  
Oil In Water ◽  
Added Water ◽  
Pseudoplastic Material

Sesame paste, usually served as a dressing in some local dishes and the desserts in Southeast Asia and the Middle East, requires mixing with water before consumption to form a thin emulsion of the oil-in-water type. Usually water addition is performed empirically and it is difficult to keep the quality of water-mixed sesame paste consistent. In this study, the rheological behavior of sesame paste with different ratios of sesame paste to added water was investigated. The sesame paste tested contains 59.71% of crude fat and 17% of protein. The ratios of sesame paste to added water (w/v) were 1 : 0.75 (T1), 1 : 1 (T2), 1 : 1.25 (T3), and 1 : 1.5 (T4), respectively. All the samples showed the properties of the viscoelastic solids. The samples T1 and T2 behaved as a pseudoplastic material, whereas the apparent viscosity of T3 and T4 remained almost unchanged with the shear rate increasing. T2 had the moderate area of thixotropy loop (57.32 Pa/s) among the tested samples and scored the highest in the sensory evaluation. Therefore, our study suggested that ratio of sesame paste to added water of 1 : 1 (w/v) is suitable for preparing dressings for different dishes.

Study on Apparent Viscosity of Semi-Solid Alloys during Rheocasting

2008 ◽  
Vol 141-143 ◽  
pp. 665-670
Author(s):  
Wen Liu ◽  
Shu Ming Xing ◽  
Mi Lan Zhang
Keyword(s):  
Energy Dissipation ◽  
Theoretical Calculation ◽  
Analytical Model ◽  
Apparent Viscosity ◽  
Metallographic Analysis ◽  
Simulated Experiment ◽  
Semi Solid ◽  
Analysis System ◽  
Solid Alloys ◽  
Good Agreement

An analytical model of apparent viscosity was built up based on analysis of energy dissipation during rheocasting. By study the evaluation law of microstructure analyzed with a quantitative metallographic analysis system for semi-solid alloys, the variation law of apparent viscosity with time has been obtained. The model was verified in the experiment of A356 alloys with a coaxial double-bucket rheometer, and the results of simulated experiment and theoretical calculation are in a good agreement.

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