Influence on the Microstructures and Properties of A356 with Vibration Pressure in Lost Form Casting

2014 ◽  
Vol 685 ◽  
pp. 7-10 ◽  
Author(s):  
Zhong Zhao ◽  
Zi Tian Fan

In order to improve the mechanical properties of A356 aluminum alloy in lost form casting (LFC), vibration and pressure were applied to solidification process of LFC, and the microstructures and the mechanical properties of the castings were compared with that of the castings in LFC without vibration and pressure. The results indicated that the grains of A356 alloy with vibration pressure in LFC became finer, and the dendrites decreased, and the equiaxed grains increased. At the same time, the porosities of the castings were significantly reduced. Compared with conventional LFC, the tensile strength, elongation, and hardness of A356 alloy with vibration pressure in LFC were all increased by 10% or above.

2006 ◽  
Vol 116-117 ◽  
pp. 453-456 ◽  
Author(s):  
Yong Lin Kang ◽  
Yue Xu ◽  
Zhao Hui Wang

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.


2014 ◽  
Vol 893 ◽  
pp. 353-356
Author(s):  
Atchara Sangchan ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin ◽  
Sirikul Wisutmethangoon

Effect of strontium (Sr) addition on the microstructure and the mechanical properties of semi-solid A356 aluminum alloy produced by GISS process were investigated in this study. Strontium addition resulted in both grain refinement and modification of eutectic Si. The maximum average ultimate tensile strength and elongation of 291.06 MPa and 17.31%, respectively, were obtained from the T6 heat-treated specimen containing 0.08wt%Sr. The excessive addition of strontium (0.2wt%Sr), however, seemed to deteriorate the mechanical properties of the alloy as a result of the Al2Si2Sr particle formation.


2021 ◽  
Vol 1033 ◽  
pp. 18-23
Author(s):  
Li Tong He ◽  
Yi Dan Zeng ◽  
Jin Zhang

To obtain an A356 aluminum alloy casting with a uniform structure and no internal shrinkage defects, ProCAST software is used to set different filling and solidification process parameters for an A356 aluminum alloy casting with large wall thickness differences, And multiple simulations are conducted to obtain optimized casting process; then, based on the process, the microstructure of the thickest and thinnest part of the casting are simulated. The size, morphology, and distribution of the simulated microstructure of the thinnest part and the thickest part of the casting are very similar. The simulated microstructure is similar to that of the actual casting. This shows that castings with uniform structure and no internal shrinkage defects can be obtained through the optimized casting process .


2020 ◽  
Vol 998 ◽  
pp. 3-8
Author(s):  
Gui Qing Chen ◽  
Gao Sheng Fu ◽  
Kai Huai Yang ◽  
Chao Sheng Lin

A356 aluminum alloy was modified by Al-Sr master alloy, and the eutectic silicon phase was changed from long needle to short fiber. Compared with the untreated, the secondary dendrite spacing decreased by 14.37 %, the tensile strength increased by 13.0 MPa, and the elongation increased by 29.51 %. After modification treatment, more developed secondary dendrites and block inclusions can be seen in the tensile fracture of A356 alloy, which is not conducive to the plasticity and fatigue resistance of the 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 ◽  
...  

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.


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Abou Bakr Elshalakany ◽  
T. A. Osman ◽  
A. Khattab ◽  
B. Azzam ◽  
M. Zaki

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.


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