Rheo-squeeze casting of semi-solid A356 aluminum alloy slurry

2010 ◽  
Vol 20 (9) ◽  
pp. 1769-1773 ◽  
Author(s):  
Wei-min MAO ◽  
Qiu ZHENG ◽  
Da-ping ZHU
Keyword(s):  
Aluminum Alloy ◽  
Squeeze Casting ◽  
A356 Aluminum Alloy ◽  
A356 Aluminum ◽  
Semi Solid

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

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

The Research on the Annulus Electromagnetic Stirring for Preparing the Semisolid A356 Aluminum Alloy Slurry

2014 ◽  
Vol 217-218 ◽  
pp. 241-246
Author(s):  
Yue Long Bai ◽  
Jun Xu ◽  
Zhi Feng Zhang
Keyword(s):  
Aluminum Alloy ◽  
Electromagnetic Stirring ◽  
A356 Aluminum Alloy ◽  
Primary Particles ◽  
A356 Aluminum ◽  
Semi Solid ◽  
Gap Width

The effects of annulus gap width, stirring power and stirring frequency on the microstructure of the semi-solid A356 aluminum alloy slurry have been investigated by the annulus electromagnetic stirring (AEMS) technology The results show that narrow annulus gap , strong stirring power and high stirring frequency are advantageous to obtain the small spherical primarymicrostructure, the smaller the annulus gap width is, the bigger the stirring power is, and the higher the stirring frequency is, the more uniform, the smaller and the more spherical the microstructure is. So the high stirring frequency, narrow annulus gap, strong stirring power are beneficial to obtain the fine and spherical semisolid microstructure in AEMS. Also the results indicate that the primary particles are globular, small and distribute homogeneously in the AEMS.

Visualization of Micro-Segregations in A356 Aluminum Alloy by a Color Etching Method

2014 ◽  
Vol 794-796 ◽  
pp. 9-14
Author(s):  
Li Gao ◽  
Yohei Harada ◽  
Shinji Kumai
Keyword(s):  
Aluminum Alloy ◽  
Grain Growth ◽  
Solid Phase ◽  
Color Difference ◽  
Water Quenching ◽  
A356 Aluminum Alloy ◽  
Dendritic Microstructure ◽  
Spheroidal Microstructure ◽  
A356 Aluminum ◽  
Semi Solid

An A356 aluminum alloy billet which has a dendritic microstructure was compressed and then partially re-melted to semi-solid state before water quenching, by which the spheroidization of Al grains was realized. A color etchant called Weck's reagent was used to characterize both the dendritic and spheroidal microstructure. In both cases, distinct color differences were observed inside Al grains by normal optical microscopy. Interestingly, a dendritic-shaped structure inside the spheroidal Al grains was visualized, which should be the reflection of the original dendrite before heating and partial re-melting. Also, the grain growth during water quenching could be clearly visualized after etching with this reagent. As a result, solid fractions could be evaluated more precisely by excluding the grain growth when measuring the area of solid phase in 2-D micrographs. In order to investigate the coloring mechanism, electron probe micro-analyses were carried out to characterize the micro-segregations inside an Al grain. Results showed that the micro-segregation of Ti had a strong correlation with the color difference. Detailed investigation found that the micro-segregation of Ti could be preserved after heating and partial re-melting due to the extremely low diffusion rate of Ti in Al.

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.

scholarly journals Microstructure and Mechanical Properties of MWCNTs Reinforced A356 Aluminum Alloys Cast Nanocomposites Fabricated by Using a Combination of Rheocasting and Squeeze Casting Techniques

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Abou Bakr Elshalakany ◽  
T. A. Osman ◽  
A. Khattab ◽  
B. Azzam ◽  
M. Zaki
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Squeeze Casting ◽  
A356 Aluminum Alloy ◽  
Multiwalled Carbon ◽  
Silicon Alloys ◽  
Alloy Matrix ◽  
Uniform Dispersion ◽  
Aluminum Alloy Matrix ◽  
A356 Aluminum

A356 hypoeutectic aluminum-silicon alloys matrix composites reinforced by different contents of multiwalled carbon nanotubes (MWCNTs) were fabricated using a combination of rheocasting and squeeze casting techniques. A novel approach by adding MWCNTs into A356 aluminum alloy matrix with CNTs has been performed. This method is significant in debundling and preventing flotation of the CNTs within the molten alloy. The microstructures of nanocomposites and the interface between the aluminum alloy matrix and the MWCNTs were examined by using an optical microscopy (OM) and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray analysis (EDX). This method remarkably facilitated a uniform dispersion of nanotubes within A356 aluminum alloy matrix as well as a refinement of grain size. In addition, the effects of weight fraction (0.5, 1.0, 1.5, 2.0, and 2.5 wt%) of the CNT-blended matrix on mechanical properties were evaluated. The results have indicated that a significant improvement in ultimate tensile strength and elongation percentage of nanocomposite occurred at the optimal amount of 1.5 wt% MWCNTs which represents an increase in their values by a ratio of about 50% and 280%, respectively, compared to their corresponding values of monolithic alloy. Hardness of the samples was also significantly increased by the addition of CNTs.

Microstructure and Mechanical Properties of Semi-Solid Die-Cast A356 Aluminum Alloy

2016 ◽  
Vol 877 ◽  
pp. 39-44
Author(s):  
Si Min Lei ◽  
Li Gao ◽  
Yohei Harada ◽  
Shinji Kumai
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
A356 Aluminum Alloy ◽  
Microstructure And Mechanical Properties ◽  
Die Cast ◽  
Microstructural Evaluation ◽  
Cast Machine ◽  
A356 Aluminum ◽  
Semi Solid ◽  
The Relationship

The present work deals with the relationship between microstructure and mechanical properties of A356 aluminum alloy which was produced via thixocasting process under different casting conditions. Feedstock billets were heated to a target temperature to obtain a semi-solid slurry with the required solid fraction. Some billets were heated to a fully-melted condition. In order to obtain fine and spheroidized Al grains, some billets for the partially melting were compressed axially by 33% at a room temperature before heating. The completely-melted and partially-melted slurries were die-cast by using a die-cast machine, and hour glass-shaped rod-type tensile specimens and small-size plate-type tensile specimens were obtained. Small cubic specimens were also collected from the die-cast products for microstructural evaluation. They were polished, and etched by Weck’s reagent. The partially-melted specimen which was compressed before heating shows the spherical Al grains. But the grain of the strain-free partially-melted specimen exhibited complicated morphology. The fully-melted specimen shows the fine and dendrite structure.

Numerical Simulation of Mould Filling in Rheocasting Process of Semisolid A356 Aluminum Alloy

2008 ◽  
Vol 141-143 ◽  
pp. 599-604
Author(s):  
Yue Long Bai ◽  
Jun Xu ◽  
Wei Min Mao ◽  
Zhi Feng Zhang ◽  
Hong Xu
Keyword(s):  
Aluminum Alloy ◽  
Apparent Viscosity ◽  
Viscosity Model ◽  
Semisolid Slurry ◽  
A356 Aluminum Alloy ◽  
Mould Filling ◽  
Forming Temperature ◽  
Simulation Results ◽  
A356 Aluminum ◽  
Semi Solid

The apparent viscosity model of the semi-solid A356 aluminum alloy, based on fitting of experimental data obtained by the Couette type viscometer, was developed in the paper. The commercial package CastSoft6.0 coupled with the model was used to simulate the mould filling of the semi-solid A356 aluminum alloy in the key-shaped component with iron cores. The simulation results showed that the position of the iron cores has an important effect on the filling of the semisolid slurry, and it is easy to obtain the completely filled key-shaped component when the iron cores were near to the inlet. The filling tests verified that the simulation results have good agreement with the experimental results. The fitting results indicated that the developed apparent viscosity model is practical and feasible and it can be used to simulate the mould filling process of the semisolid A356 aluminum alloy slurry. Also the parameters were optimized and the optimum parameters are as follows: the inject pressure is more than 15MPa, the inlet velocity is more than 1.73m/s and the forming temperature is over 585 °C.

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