Semi-Solid Processing of Nano-SiCP/ Al-Si Composites and Mechanical Properties with Rheo-Casting

2019 ◽  
Vol 285 ◽  
pp. 33-38
Author(s):  
Shu Sen Wu ◽  
Du Yuan ◽  
Qiang Chen ◽  
Shu Lin Lü ◽  
Zhi Wei Huang
Keyword(s):  
A356 Alloy ◽  
Average Diameter ◽  
Sem Analysis ◽  
Nano Particles ◽  
Mechanical Stirring ◽  
Sic Particles ◽  
New Process ◽  
The Matrix ◽  
A356 Aluminum ◽  
Semi Solid

Generally nano-SiC particles are difficult to be added into molten aluminum metals because of poor wettability. Nano-SiC particles reinforced A356 aluminum alloy composites were prepared by a new process, i.e., a molten-metal process combined with mechanical stirring at semi-solid state and ultrasonic vibration method. The nano particles were β-SiCp with an average diameter of 40 nm, and pre-oxidized at about 850°C to form an oxide layer with thickness of approximately 3.6 nm. The SEM analysis results show that nano-SiC particles are dispersed well in the matrix and no serious agglomeration is observed. The tensile strength and elongation of the 2wt.% nano-SiCp/A356 composite in as-cast state are 259 MPa and 5.3%, and they are improved by 20% and 15% respectively compared with those of the A356 alloy.

Behavior of A356 Alloy in Semi-Solid State Produced by Mechanical Stirring

2011 ◽  
Vol 402 ◽  
pp. 331-336 ◽  
Author(s):  
Salman Nourouzi ◽  
Amin Kolahdooz ◽  
Mohammad Botkan
Keyword(s):  
Mechanical Properties ◽  
Die Casting ◽  
A356 Alloy ◽  
Mold Temperature ◽  
A356 Aluminum Alloy ◽  
Micro Structure ◽  
Mechanical Stirring ◽  
Aluminum Silicon Alloy ◽  
A356 Aluminum ◽  
Semi Solid

This investigation studied semi-solid (SSM) aluminum-silicon alloy produced by mechanical stirring. Aluminum alloys produced by this method, are widely used instead of conventional die casting and forging processes. In this research by using a mechanical stirrer slurry maker, the effects of stirring speed, the solid fraction percent and mold temperature are investigated on micro-structure and hardness of A356 aluminum alloy in semi-solid casting. By optimizing the forming parameters, dendrite microstructure changes to globular and mechanical properties improves. This is because of breaking and globularizing dendrites of primary α-AL phase. It is determined that stirring temperature of 608°C and stirring speed of 300 RPM leads to the uniform grains distribution and therefore arrives to better hardness for the produced billets.

Study on Microstructures and Mechanical Properties of Rheo-Die Casting Semi-Solid A356 Aluminum Alloy

2006 ◽  
Vol 116-117 ◽  
pp. 453-456 ◽  
Author(s):  
Yong Lin Kang ◽  
Yue Xu ◽  
Zhao Hui Wang
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Die Casting ◽  
A356 Alloy ◽  
Experimental Results ◽  
A356 Aluminum Alloy ◽  
Microstructures And Mechanical Properties ◽  
A356 Aluminum ◽  
Semi Solid

In this paper, with a newly self-developed rotating barrel rheomoulding machine(RBRM), microstructures and mechanical properties of rheo-die casting A356 alloy were studied. In order to clearly show the characteristic of rheo-die casting, liquid die casting and semi-solid casting were done too. The experimental results showed that microstructures of rheo-die casting were composed of solid grains, which were finer and rounder, and had fewer pores. In the three technologies, integrated mechanical properties of semi-solid rheo-die casting were the best.

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.

Study on Creep Properties of SiCp/AZ61 Composites

2011 ◽  
Vol 189-193 ◽  
pp. 4227-4230
Author(s):  
Hong Yan ◽  
Zhi Min Huang
Keyword(s):  
Thermal Analysis ◽  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Dynamic Mechanical Thermal Analysis ◽  
Creep Properties ◽  
Casting Technique ◽  
Sic Particles ◽  
The Matrix ◽  
Semi Solid

SiCp/AZ61 composites reinforced with SiC particles were fabricated by semi-solid stirring-melt casting technique. The creep properties of the composites have been studied by dynamic mechanical thermal analysis, micro-structural and XRD observation. The results show that the matrix grains were refined obviously at high temperature with SiC particles introducing and the creep properties of SiCp/AZ61 composites were improved comparing with AZ61 alloy. SiC particles were substituted for Mg17Al12 phase that was easily intenerated at high temperature on grain boundaries. The pinning of SiC particles prevents dislocation and slip of grain boundary at high temperature.

Influence of Nanodispersions on Properties and Microstructure Features of Cast and T6 Heat-Treated Al Si Hypoeutectic Alloys

2012 ◽  
Vol 192-193 ◽  
pp. 76-82
Author(s):  
Iman El Mahallawi ◽  
Hoda Abdelkader ◽  
Laila Shehata ◽  
Asmaa Amer ◽  
Joachim Mayer ◽  
...  
Keyword(s):  
Lamellar Spacing ◽  
Light Metal ◽  
Nano Particles ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
Mechanical Stirring ◽  
Heat Treated ◽  
Cast Alloys ◽  
Semi Solid ◽  
Function Relationship

Cast light metal alloys have retained their importance and unique characteristics as first candidates when cost-function relationship is considered. Hypoeutectic aluminum silicon alloys as (A356) exhibit several specific and interesting properties that qualify them to be used in many automotive and aeronautical applications. Evidence of significant enhancement in strength in the properties of Al-Si cast alloys by incorporating nano-particles have been recently presented. The present study aims at developing nano-dispersed Al-Si alloys with suitable casting methods that assure the dispersion of the nano-particles. In this work a number of cast samples of A356 were prepared by rheo-casting in a specially designed and built furnace unit allowing for the addition of the nano-particles into the molten Al-Si alloy in the semi-solid state with mechanical stirring. The microstructural features and the mechanical properties of the cast and T6 heat treated samples were investigated. The results obtained in this work showed enhancement in the mechanical strength of the nano-dispersed alloys, accompanied by significant increase in the elongation percentage, supported by evidence of refined dendrite arms length, and inter-lamellar spacing.

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.

Fabrication of Aluminum Nanocomposite by Ultrasonic Spray Deposited Sheet Bonding

2014 ◽  
Author(s):  
Mina Bastwros ◽  
Gap-Yong Kim ◽  
Jie Wang
Keyword(s):  
Laminate Composite ◽  
Spray Deposition ◽  
Matrix Material ◽  
Reference Sample ◽  
Nano Particles ◽  
Ultrasonic Spray ◽  
The Matrix ◽  
Three Point Bend Test ◽  
Point Bend ◽  
Semi Solid

Reinforcement with nano-sized particles offers a promising potential to significantly enhance the mechanical, electrical, and thermal properties of a metal matrix composite (MMC). One of the challenges of synthesizing nanocomposites, however, has been the dispersion and control of the nano-reinforcement materials. In this study, a laminate nanocomposite has been synthesized by incorporating ultrasonic spray deposition technique. An ultrasonic spray deposition system was used to deposit nano-particles on substrate foils, which were consolidated to synthesize a laminate composite. Aluminum 6061 (Al6061) alloy foils were used as the matrix material. Nano-silicon carbide (SiC) particles were used as the reinforcement phase (deposited layer). The sprayed foils were stacked together to form the composite. The composite was then consolidated by hot compaction in the semi-solid regime of the Al6061. A three point bend test was carried out to evaluate the mechanical properties. In addition, the suspension and spraying parameters that control the deposited microstructure was studied to help control the final properties of the deposited structure. The yield and ultimate flexural strength of the SiC sprayed Al6061 laminate composite showed an increase (32% and 15%, respectively) compared with that of the unsprayed sample (reference sample) processed at the same condition.

Study on the Reinforcement of Aluminum Alloy A356 Using SiC Particles by Mechanical Stirring

2011 ◽  
Vol 399-401 ◽  
pp. 368-371
Author(s):  
Hong Xia Gao ◽  
Yu Hui Zhang ◽  
Jian Xiu Liu ◽  
Gai Yun Yang
Keyword(s):  
Mechanical Property ◽  
Volume Fraction ◽  
A356 Alloy ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
Mechanical Stirring ◽  
Sic Particles ◽  
Size Of Particles ◽  
Particle Addition ◽  
Sic Particle

This paper is to research the manufacturing process of A356 alloy matrix composites reinforced by SiC particles by mechanical stirring and how the size of particles ,volume fraction affect mechanical property has been studied , too. The text results revealed that larger particles especially particle size larger than 30um were suitable using this technique, meanwhile, it will hard to adding particles into the alloy when particle lower than 20um size. The effects of SiC particle addition on the hardness properties of A356 alloy and with higher volume fraction particles lead to greater hardness.

Numerical Modeling of Die Filling of Semi-Solid A356 Aluminum Alloy

2008 ◽  
Vol 141-143 ◽  
pp. 605-610 ◽  
Author(s):  
A. Foroughi ◽  
Hossein Aashuri ◽  
A. Narimannezhad ◽  
Ali Khosravani ◽  
M. Kiani
Keyword(s):  
A356 Alloy ◽  
Solidification Process ◽  
A356 Aluminum Alloy ◽  
Finite Element Software ◽  
Die Filling ◽  
Simulation Results ◽  
A356 Aluminum ◽  
Semi Solid ◽  
Constitutive Parameters ◽  
Aluminum A356 Alloy

Computer base and simulation technique have been applied for modeling the semi-solid die filling and part of the solidification process of aluminum A356 alloy. A fairly simple one-phase rheological model has been implemented into a fluid flow finite element software Procast, to solve the partial differential equations. This model is purely viscous nature and is implemented in the power law cut-off model of Procast. The constitutive parameters of this model were determined for a rheocast A356 alloy. Using these parameters and comparing the simulation results with experimental data showed good correlation with the model prediction. The designed die for rheocasting was applied for the production of a small propeller with thin section.

An AEM characterization of interfacial reactions in Al-MMC's reinforced with as-received and oxidized SiC particles

1991 ◽  
Vol 49 ◽  
pp. 734-735
Author(s):  
J.G. Legoux ◽  
G. L'Espérance ◽  
M. Suéry
Keyword(s):  
Interfacial Reactions ◽  
Processing Route ◽  
Air Oxidation ◽  
Sic Particles ◽  
Transmission Electron ◽  
Microscopy Investigation ◽  
The Matrix ◽  
History Of ◽  
Semi Solid ◽  
Material Fabrication

Interfacial reactions in MMC's can affect the mechanical properties of the material by changing the composition of the matrix and by forming new compounds at the matrix/ceramic interfaces. These reactions depend on the surface chemistry of the reinforcement, such as the presence of SiO2 produced by air oxidation of raw SiC particles. These reactions also depend on the processing route, particularly the thermal history of the material (fabrication or subsequent heat treatment or remelting). This paper presents results of an analytical transmission electron microscopy investigation of interfaces observed in Al-1% Mg alloys reinforced with 10 vol. % SiC particles. The composites were produced by the compocasting technique (semi-solid route) using as-received and oxidized SiC particles. The particles were oxidized in air at 1100°C for various times to produce oxidation levels ranging from 0-16 wt % measured by wet analysis.

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