Refinement of Primary Silicon Grains in Semi-Solid Al-25%Si Hypereutectic Aluminum Alloy Slurry

2019 ◽  
Vol 285 ◽  
pp. 153-160 ◽  
Author(s):  
Wei Min Mao ◽  
Peng Yu Yan ◽  
Z.K. Zheng
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Research Work ◽  
Good Method ◽  
Primary Silicon ◽  
Pouring Temperature ◽  
Channel Bend ◽  
Traditional Process ◽  
Semi Solid ◽  
Inner Channel

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.

Preparation of Semi-Solid A390 Aluminum Alloy Slurry through a Serpentine Pouring Channel

2019 ◽  
Vol 285 ◽  
pp. 169-175 ◽  
Author(s):  
Wei Min Mao ◽  
Peng Yu Yan ◽  
Z.K. Zheng
Keyword(s):  
Aluminum Alloy ◽  
Good Method ◽  
Primary Silicon ◽  
Forming Process ◽  
Pouring Temperature ◽  
Average Shape ◽  
Traditional Process ◽  
Semi Solid ◽  
A390 Alloy ◽  
Inner Channel

In order to study the possibility of refining the primary silicon grains in the microstructure of hypereutectic Al-Si alloy through a serpentine pouring channel, the semi-solid slurry of A390 aluminum alloy was prepared through a water-cooled copper serpentine pouring channel, which is a new method proposed recently for semi-solid forming process, and the effect of pouring temperature on the slurry microstructure was investigated. The results show that the slurry of A390 aluminum alloy with refined primary silicon grains can be prepared under given conditions and especially when the pouring temperatures is 690°C, the primary silicon grains can be refined obviously, the equivalent silicon grain size is 19.7mm and the average shape factor is about 0.7. The analysis shows that the chilling effect of the inner channel wall precipitates a large number of primary silicon nuclei, and so the primary silicon grains are refined greatly. Meanwhile, the subsequent alloy melt washing also promotes the separation of primary silicon grains from the inner wall and the primary silicon grains are further refined. The work undertaken demonstrates eventually that the serpentine pouring channel process is a good method for refining the primary silicon grains in hypereutectic A390 alloy rather than using chemical fining agent phosphorus as in traditional process, and provides an alternative process choice.

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
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Shape Factor ◽  
Primary Phase ◽  
High Quality ◽  
Pouring Temperature ◽  
6061 Aluminum Alloy ◽  
Serpentine Channel ◽  
Channel Surface ◽  
Semi Solid

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.

Formation of Globular Microstructure in A380 Aluminum Alloy by Cooling Slope Casting

2011 ◽  
Vol 264-265 ◽  
pp. 272-277 ◽  
Author(s):  
Nurşen Saklakoğlu ◽  
S. Gencalp ◽  
Şefika Kasman ◽  
İ.E. Saklakoğlu
Keyword(s):  
Aluminum Alloy ◽  
Slope Angle ◽  
Casting Process ◽  
Solid Particles ◽  
Inclined Plate ◽  
Pouring Temperature ◽  
Cooling Slope ◽  
Semi Solid ◽  
Cooling Slope Casting ◽  
The Many

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.

Semi-Solid 6061 Aluminum Alloy Slurry Prepared by Serpentine Channel Pouring Process and its Rheo-Diecasting

2022 ◽  
Vol 327 ◽  
pp. 279-286
Author(s):  
Nai Yong Li ◽  
Wei Min Mao ◽  
Xiao Xin Geng ◽  
Peng Yu Yan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Ductile Fracture ◽  
Fracture Mechanism ◽  
Pouring Temperature ◽  
6061 Aluminum Alloy ◽  
Serpentine Channel ◽  
Die Cast ◽  
Semi Solid

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.

Effect of the Parameters in Inverted Cone-Shaped Pouring Channel Process on the Microstructure of Semi-Solid 7075 Aluminum Alloy Slurry

2012 ◽  
Vol 192-193 ◽  
pp. 415-421 ◽  
Author(s):  
Bin Yang ◽  
W.M. Mao ◽  
Jian Nan Zeng ◽  
Xiao Jun Song
Keyword(s):  
Aluminum Alloy ◽  
Structural Parameters ◽  
Contact Condition ◽  
Heat Extraction ◽  
7075 Aluminum Alloy ◽  
Pouring Temperature ◽  
Interior Surface ◽  
Channel Process ◽  
Inverted Cone ◽  
Semi Solid

The semi-solid slurry of 7075 aluminum alloy was prepared by using an innovative non-stirring technology that can be called inverted cone-shaped pouring channel process (ICSPC). The effect of pouring temperature and structural parameters of the channel on the microstructure of semi-solid 7075 aluminum alloy slurry was investigated. The experimental results reveal that when keeping the pouring temperature within some range, the slurry with spherical primary α(Al) grains can be prepared by ICSPC process, and with the decline of the pouring temperature, the microstructure of semi-solid 7075 aluminum alloy is more desirable under the same channel. The appropriate combination of channel length and interior surface slope can also give rise to a transition of the growth morphology of primary α(Al) from coarse dendritic to coarse particle-like and further to fine-globular at the same pouring temperature. In ICSPC process, numerous effective heterogeneous nucleation takes place in the melt as it flowed along the interior surface of the channel and the morphology of primary α(Al) grains is virtually determined by the degree of contact condition between the superheat melt and the interior surface of the channel. A better contact condition stands for a stronger heat extraction from the melt, and will finally appear as a remarkable increase of primary α(Al) grains survived in the melt, which will conspicuously promote the spherical growth of the primary α(Al) grains.

THE OPTIMIZING CONDITIONS BY TAGUCHI METHOD FOR FABRICATING SEMI-SOLID Al–Zn–Mg ALLOY SLURRY BY COOLING PLATE METHOD

2010 ◽  
Vol 17 (02) ◽  
pp. 185-188 ◽  
Author(s):  
SUNG-YONG SHIM ◽  
HYUNG-WON PARK ◽  
IN-SANG JEONG ◽  
SU-GUN LIM
Keyword(s):  
Grain Size ◽  
Aspect Ratio ◽  
Design Method ◽  
Solid Material ◽  
Mg Alloy ◽  
Image Analyzer ◽  
Pouring Temperature ◽  
Plate Method ◽  
Cooling Plate ◽  
Semi Solid

In order to optimize the condition for the semi-solid Al–Zn–Mg aluminium alloy fabricated by cooling plate method, the Taguchi design was used. The cooling plate method effectively separating the grains formed from the mold wall can be used to form a semi-solid material by flowing molten metal over an inclined Cu plate and casting in a mold for the near-net shape component. In Taguchi's design method, the higher signal vs noise (S/N) ratio the better. Therefore, the manufacturing conditions were arranged as a table of orthogonal arrays (L9(34)), and the influence of two factors, pouring temperature and cooling plate angle, was examined. From the observed microstructures, the grain size and aspect ratio were measured by image analyzer. The results indicated that the pouring temperature exerts the main effect on the spherical microstructures since the S/N ratio, which is the sensibility of the surrounding environment, was the highest. The optimum condition for the Al–Zn–Mg alloy was a cooling plate angle of 40° and a pouring temperature of 680°C. The grain size and aspect ratio were 70 μm and 1.3, respectively.

Investigation of the Relationships between Billet Reheating and Semi-Solid Die-Casting

2010 ◽  
Vol 97-101 ◽  
pp. 306-310 ◽  
Author(s):  
Xiang Lin Yin ◽  
Yi Tao Yang ◽  
Yu Peng Shao ◽  
Guang Jie Shao
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Aluminum Alloy ◽  
Die Casting ◽  
Surface Hardness ◽  
A356 Aluminum Alloy ◽  
Final Temperature ◽  
A356 Aluminum ◽  
Semi Solid ◽  
The Relationship

The non-dendritic of A356 aluminum alloy billet was reheated to meet the requirements of the semi-solid microstructure by three different kinds of power, achieving the same final temperature of 863K. Subsequently, under the same conditions of die-casting (thixoforming), the microstructure was observed, surface hardness and tensile properties were measured. Afterwards, quantitative analysis was made for the microstructure of the reheated semi-solid of billet and the thixoforming parts. The results showed that the larger induction reheating power of the billet, the smaller the grain size of its microstructure and the higher surface hardness and the better mechanical properties of its thixoforming sample. Finally, through studying on the relationship between the microstructure of the semi-solid billet of A356 aluminum alloy and the mechanical properties of the thixoforming sample, we primarily achieved the reverse design of microstructure.

Experimental Investigation on the Effect Due to Mould Vibrations on Mechanical and Metallurgical Properties of Aluminum Alloy (A-1050)

2021 ◽  
Vol 9 (1) ◽  
pp. 77-86
Author(s):  
Sujith Bobba ◽  
Sambasiva Rao Mukkollu ◽  
Z. Leman ◽  
Harish Babu Bachina
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Research Work ◽  
Casting Process ◽  
Vibration Frequencies ◽  
Alloy Specimen ◽  
Pouring Temperature ◽  
Casting Aluminum Alloy ◽  
Casting Aluminum ◽  
Made In

In the current research work performed, the consequences caused in the casting aluminum alloy specimen due to mechanical mould vibrations are examined. Mould vibration throughout the casting provides decreased rate of shrinkage, good morphology, surface finish and lesser probability of hot tear. In this research work, the effect of mould vibration during solidification of Aluminum A-1050 alloys for dissimilar values of wavelengths at a permanent pouring temperature has been investigated to understand the modification in microstructure and mechanical properties after casting. The Al A-1050 casting has been made in a metal mould with different vibrations. The frequencies are varied from 15Hz to 50 Hz during the casting process. A casting has been made with different vibration as well to compare the results of castings with vibration frequencies. The experimental outcomes exhibited substantial grain refinement and significant increase in tensile strength and hardness of the castings with mechanical mould vibration during the duration and after solidification.

Preparation of Globular Microstructure Aluminum Alloy Using Cooling Slope Casting as Feed Material for Equal Channel Pressing Process

2014 ◽  
Vol 1024 ◽  
pp. 247-250 ◽  
Author(s):  
Nguyen Van Thuong ◽  
Zuhailawati Hussain ◽  
Anasyida Abu Seman ◽  
T.D. Huy
Keyword(s):  
Aluminum Alloy ◽  
Mild Steel ◽  
Casting Process ◽  
Pouring Temperature ◽  
Feed Material ◽  
Globular Microstructure ◽  
Cooling Slope ◽  
Semi Solid ◽  
Cooling Slope Casting ◽  
Steel Mould

Equal channel angular pressing (ECAP) could be used to achieve ultra fine grains in bulk aluminum alloy through severe plastic deformation. Typically a feed material of as-cast aluminum alloys is used with a typical hypoeutectic solidification structure, consisting of primary aluminum dendrites and interdendritic network of lamellar eutectic silicon. On the other hand, semi-solid metal casting provides non-dendritic and globular microstructure which is one of a considerable factor in obtaining homogenous microstructure after ECAP. This work is an attempt to produce aluminum alloy with globular microstructure using cooling slope semi-solid casting process which is believed suitable as a feedstock for ECAP. The aim of this work described in this paper was to understand of microstructural evolution of aluminum structure during cooling slope casting process. Two experiments were carried out. A sample was casted via a cooling slope into a vertical cold mild steel mould at pouring temperature of 640°C. Cooling slope length of 250 mm, slope temperature of room temperature and tilt angle of 60owas applied. Another sample was casted directly into a vertical cold mild steel mould at pouring temperature of 640°C. The primary α-Al phases in the sample that casted without cooling slope was mostly in dendritic throughout the section of sample whilst the primary α-Al phases transformed completely into non-dendritic in the sample that was casted via the cooling slope. Therefore, the transformation is believed resulted from the effect of cooling slope

Sign in / Sign up

Export Citation Format

Share Document