Effect of Serpentine Channel Pouring Process on the Microstructure of Semi-Solid 6061 Aluminum Alloy Slurry

2022 ◽  
Vol 327 ◽  
pp. 255-262
Author(s):  
Nai Yong Li ◽  
Wei Min Mao ◽  
Xiao Xin Geng ◽  
Peng Yu Yan

The semi-solid slurry of 6061 aluminum alloy was prepared by the serpentine channel pouring process. The influence of graphite serpentine channel and copper serpentine channel on the slurry was comparative analyzed. The effect of pouring temperature on the slurry microstructure was also investigated. The results indicate that both copper and graphite serpentine channel can be used to prepare semi-solid slurry with spherical primary grains. Compared with a permanent casting, the microstructure of the semi-solid slurry was significantly improved and refined. With the increase of pouring temperature, the average equivalent grain diameter of the primary phase grains in the semi-solid slurry increases gradually, but the shape factor decreases gradually. When the pouring temperature increased from 675 °C to 690 °C, a high quality semi-solid slurry can be obtained. Comparing the two kinds of serpentine channel, it is found that the copper serpentine channel can make the primary grains finer, and the average equivalent grain size was 63 μm. However, the solidified shell near the inner graphite serpentine channel surface was thinner than that of the copper serpentine channel. In conclusion, the graphite serpentine channel is more suitable for preparing semi-solid 6061 aluminum alloy slurry.

2022 ◽  
Vol 327 ◽  
pp. 279-286
Author(s):  
Nai Yong Li ◽  
Wei Min Mao ◽  
Xiao Xin Geng ◽  
Peng Yu Yan

Semi-solid 6061 aluminum alloy slurry was prepared by a graphite serpentine channel and its rheo-diecasting experiment was carried out on the slurry. The influence of pouring temperature on the microstructure evolution and mechanical properties of the rheo-diecasting were investigated. The microstructure and fracture mechanism of traditional die cast tensile specimens and rheo-diecast tensile specimens were compared and investigated. The results indicate that the microstructure of rheo-diecast tensile specimens is composed of spherical primary α-Al grains and fine secondary solidified α2-Al grains. When the pouring temperature increased from 660 °C to 720 °C, the average equivalent grain diameter of primary α-Al grains increased from 42 μm to 58 μm, and the shape factor decreased from 0.82 to 0.73. As the pouring temperature increases, the as-cast tensile strength and elongation of tensile specimens both increase first and then decrease. When the pouring temperature was 690 °C, the best mechanical properties were obtained, with as-cast tensile strength of 142.93 MPa and as-cast elongation of 4.86%. The fracture mechanism of traditional die casting is mainly ductile fracture, and the fracture mechanism of rheo-diecasting is a mixed fracture of intergranular fracture and ductile fracture.


2019 ◽  
Vol 285 ◽  
pp. 153-160 ◽  
Author(s):  
Wei Min Mao ◽  
Peng Yu Yan ◽  
Z.K. Zheng

s: The semi-solid slurry of Al-25%Si hypereutectic aluminum alloy was prepared through a copper serpentine pouring channel, the effect of pouring temperature and numbers of channel bend on the slurry microstructure was investigated. The results show that the primary silicon grains in Al-25%Si hypereutectic alloy solidified at a traditional condition are very large and the average silicon grain size is about 65.3μm, however, when the liquid Al-25%Si alloy is poured through a copper serpentine pouring channel, the primary silicon grains are fined obviously. If the channel has three bends and the pouring temperature is 747°C,the average silicon grain size in the slurry is about 33.7μm. If the channel has four bends and the pouring temperature is 747°C, the average silicon grain size in the slurry is about 30.9μm. If the channel has seven bends and the pouring temperature is 747°C, the average silicon grain size in the slurry is about 28.6μm. The analysis shows that the chilling effect of the inner channel wall precipitates primary silicon nuclei, and so the primary silicon grains of Al-25%Si alloy are fined greatly. Meanwhile, the subsequent washing of the alloy melt also promotes the separation of primary silicon grains from the inner wall and the primary silicon grains are further fined. The above research work demonstrates eventually that the copper serpentine pouring channel process is a good method for fining the primary silicon grains in hypereutectic Al-25%Si alloy rather than using chemical fining agent phosphorus as in traditional process.


2020 ◽  
Vol 17 (2) ◽  
pp. 197
Author(s):  
Syaharuddin Rasyid ◽  
Abram Tangkemanda ◽  
Muh. Hasmar Hasbullah ◽  
Muh. Andra Al-Fandi

This study aims to analyze the effect of the stirrer model, stirring rotation (400, 500, 600 rpm), for 20 seconds, and pouring temperature (565, 570, and 5750C) on the microstructure and mechanical properties of the aluminum alloy ADC12. The methods of research are a) preparing material aluminum alloy ADC12, b) making molds, c) casting, d) making specimens for testing, e) micro structure testing and hardness testing, f) analyzing data using Microsoft excel applications. Results of the study show that the smallest grain size occurs in casting parameters: stirrer angle 00, 600 rpm rotation, and pouring temperature 5650C with a value of 27.715 µm. The biggest shape factor occurs in casting parameters: stirrer angle 00, rotation 600 rpm, and pouring temperature 5650C with a value 0.76. The highest hardness occurs in casting parameters: stirrer angle 00, rotation 600 rpm, and pouring temperature 5650C with a value 88.0 HB.


2008 ◽  
Vol 141-143 ◽  
pp. 163-168 ◽  
Author(s):  
Xiang Jie Yang ◽  
Hong Min Guo

Rheo-die casting (RDC) based on LSPSF (low superheat pouring with a shear field) rheocasting process has been exploited. In case of secondary die casting aluminum alloy YL112, LSPSF allowed for preparation of sound semi-solid slurry in 15-20s that fully meet the production rate of HPDC, the primary α-Al exhibiting a mean equivalent diameter of 70 μm and shape factor of 0.93, without any entrapped eutectic. Compared to conventional HPDC, RDC improves microstructures in castings. Secondary solidification of semi-solid slurry takes place uniformly throughout the entire cavity, producing an extremely fine and uniform microstructure. The experimental results show the RDC 380 alloy has much improved integrity and mechanical properties, particularly elongation, and heat treatment can be used to enhance the mechanical properties.


2011 ◽  
Vol 264-265 ◽  
pp. 272-277 ◽  
Author(s):  
Nurşen Saklakoğlu ◽  
S. Gencalp ◽  
Şefika Kasman ◽  
İ.E. Saklakoğlu

Thixoforming and related semi-solid processing (SSP) methods require thixotropic materials. One of the many SSP techniques is the cooling slope (CS) casting process, which is simple and has minimal equipment requirements, and which is able to produce feedstock materials for semisolid processing. When the feedstock is reheated to the semisolid temperature range, non-dendritic, spheroidal solid particles in a liquid matrix suitable for thixoforming are obtained. In this study, equipment for the CS technique was first established, and then the effects of the pouring temperature and inclined slope angle on the microstructures of A380 aluminum alloy (ISOAlSi8Cu3Fe) were studied. Optimum parameters for thixoforming experiments were selected, and it was found that the microstructure produced by the inclined plate depended on its angle and the pouring temperature.


2016 ◽  
Vol 26 (7) ◽  
pp. 1820-1825 ◽  
Author(s):  
Shu-jian CHENG ◽  
Yu-hong ZHAO ◽  
Hua HOU ◽  
Yu-chun JIN ◽  
Xiao-xiao GUO

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1168 ◽  
Author(s):  
Zhen Xu ◽  
Sixue Wang ◽  
Hongbin Wang ◽  
Hua Song ◽  
Shengli Li ◽  
...  

In this study, a twin-roll casting sheet of 6061 aluminum alloy was cooled using furnace, asbestos, air, wind and water. The effect of cooling rate on the microstructure and properties of twin-roll casting 6061 aluminum alloy sheet were studied. Optical microscope, scanning electron microscope, X-ray diffraction, microhardness tester and universal tensile machine were used to observe the microstructure and properties of twin-roll casting sheet of 6061 aluminum alloy. The results show that the higher the cooling rate, the smaller the grain size of the alloy and the smaller the number of precipitated phases in the matrix. Uniform grain size of the alloy could be obtained at a stable cooling rate. The hardness, tensile strength and elongation of the twin-roll casting sheet increased with cooling rate. Under wind cooling condition, the twin-roll casting sheet demonstrated excellent comprehensive performance, i.e., 88 MPa of yield strength, 178 MPa of tensile strength and 15% of elongation, respectively. A quantitative Hall–Petch relation was established to predict the yield strength of 6061 twin-roll casting sheets with different grain sizes and cooling rate.


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