Preparation of Large-Diameter Semi-Solid 7075 Aluminum Alloy Billets

2008 ◽  
pp. 361-365
Author(s):  
Wei Wei Wang ◽  
Jian Li Song ◽  
Shou Jing Luo
Keyword(s):  
Aluminum Alloy ◽  
Large Diameter ◽  
7075 Aluminum Alloy ◽  
Semi Solid

Preparation of Large-Diameter Semi-Solid 7075 Aluminum Alloy Billets

2008 ◽  
Vol 141-143 ◽  
pp. 361-365 ◽  
Author(s):  
Wei Wei Wang ◽  
Jian Li Song ◽  
Shou Jing Luo
Keyword(s):  
Aluminum Alloy ◽  
Heating Temperature ◽  
Large Diameter ◽  
Processing Parameters ◽  
7075 Aluminum Alloy ◽  
Dimensional Precision ◽  
Average Grain Size ◽  
Wide Range ◽  
Fine Microstructure ◽  
Semi Solid

Preparation of semi-solid microstructure of 7075 aluminum alloy industrial extrusion billets was studied in this paper. A new semi-solid microstructure preparation process is proposed. In the treatment, melting-stirring and predeformation of the alloy billets are not required. An ideal microstructure and higher dimensional precision of the billet can be obtained only with a direct heating and insulation method. The influences of different heating temperatures and insulation time on the microstructure evolution were studied with orthogonal testing methods. The obtained microstructure was observed and analyzed by optical microscopy, and the formation mechanism of the semi-solid microstructure is further discussed. The results indicate that a fine microstructure can be obtained with the proposed process and the processing parameters can be controlled over a wide range. Also, the grain microstructure obtained by the present process is better than that of the SIMA. For 7075 aluminum alloy billets, perfect fine equiaxial grains can be obtained under a heating temperature of 620°C and a holding time of about 25 minutes. The average grain size is around 80μm.

Characterizing the Effect of Processing Parameters on Temperature Distribution of 7075 Aluminum Alloy Slurry Prepared by Enthalpy Control Process

2022 ◽  
Vol 327 ◽  
pp. 263-271
Author(s):  
Gan Li ◽  
Jin Kang Peng ◽  
En Jie Dong ◽  
Juan Chen ◽  
Hong Xing Lu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Temperature Difference ◽  
Initial Temperature ◽  
Control Process ◽  
Processing Parameters ◽  
Heating Time ◽  
7075 Aluminum Alloy ◽  
Semi Solid ◽  
7075 Alloy ◽  
Slurry Preparation

There is a strong demand for high-strength aluminum alloys such as 7075 aluminum alloy to be applied for rheocasting industry. The overriding challenge for the application of 7075 alloy is that its solid fraction is very sensitive to the variation of temperature in the range of 40% ~ 50% solid fraction, which inevitably narrows down the processing window of slurry preparation for rheocasting process. Therefore, in this work, a novel method to prepare semi-solid slurry of the 7075 alloy, so called Enthalpy Control Process (ECP), has been developed to grapple with this issue. In the method, a medium-frequency electromagnetic field was applied on the outside of slurry preparation crucible to reduce the temperature difference throughout the slurry. The effect of processing parameters, including heating power, heating time, the initial temperature of crucible and melt weight, on the temperature field of the semi-solid slurry was investigated. The results exhibited that although the all the processing parameters had a great influence on the average temperature of the slurry, heating time was the main factor affecting the maximum temperature difference of the slurry. The optimum processing parameters during ECP were found to be heating power of 7.5 KW, the initial temperature of crucible of 30 °C ~ 200 °C and melt weight of 2 kg.

Creep of Rheocast 7075 Aluminum Alloy at 300 °C

2013 ◽  
Vol 372 ◽  
pp. 288-291 ◽  
Author(s):  
Saravut Thongkam ◽  
Sirikul Wisutmethangoon ◽  
Jessada Wannasin ◽  
Suchart Chantaramanee ◽  
Thawatchai Plookphol
Keyword(s):  
Aluminum Alloy ◽  
Creep Rate ◽  
Creep Deformation ◽  
Minimum Creep Rate ◽  
7075 Aluminum Alloy ◽  
Stress Range ◽  
Dislocation Glide ◽  
Semi Solid ◽  
Power Law Creep ◽  
Rupture Strain

Creep of rheocast 7075-T6 aluminum alloy produced by the Gas Induced Semi-Solid (GISS) process was investigated at temperature of 300 °C and stress range of 20-70 MPa and compared to that of wrought 7075-T651 aluminum alloy. The rheocast 7075-T6 alloy exhibited lower minimum creep rate and longer rupture time than the wrought 7075-T651 alloy. The total rupture strain of the rheocast alloy was shorter than that of the wrought one. According to the power law creep, the stress exponents, n of the rheocast 7075-T6 and the wrought 7075-T651 alloys were 5.9 and 7.9 respectively. Based on the determined n values, the creep deformation of both alloys was possibly controlled by the dislocation glide and climb-controlled mechanism.

Effects of Solid Fractions in a Slurry Die Casting Process on Defects of 7075 Aluminum Alloy

2015 ◽  
Vol 752-753 ◽  
pp. 7-10 ◽  
Author(s):  
Waraporn Jumpol ◽  
Jessada Wannasin ◽  
Somjai Janudom ◽  
Rungsinee Canyook ◽  
Thawatchai Plookphol ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Solid Fraction ◽  
Die Casting ◽  
Casting Process ◽  
7075 Aluminum Alloy ◽  
Die Casting Process ◽  
Semi Solid

The effects of Gas Induced Semi-Solid (GISS) in the slurry die casting process on defects of 7075 aluminum alloy were studied, different initial solid fractions with 10, 15, and 20 sec of rheocasting time were investigated. The results showed that the percentage of porosity in semi-solid die casting was smaller than in the liquid die casting. In terms of the initial solid fraction in 7075 aluminum alloy, it was found that the defects were found when the initial solid fraction was high. In addition.

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.

Simulation and Research on the Rheocasting Process of 7075 Aluminum Alloy

2010 ◽  
Vol 129-131 ◽  
pp. 482-489 ◽  
Author(s):  
Nan Li ◽  
Shu Ming Xing ◽  
Pei Wei Bao
Keyword(s):  
Aluminum Alloy ◽  
Shrinkage Porosity ◽  
Casting Temperature ◽  
7075 Aluminum Alloy ◽  
Porosity Distribution ◽  
Casting Quality ◽  
Liquid Phases ◽  
Segregation Phenomenon ◽  
Semi Solid ◽  
Wrought Aluminum

Taking the 7075 aluminum alloy as an example, this paper did some simulation work on temperature, flow field and shrinkage porosity distribution in the rheocasting process using the simulation casting software PROCAST. Effects of the casting temperature and filling speed on casting quality as well as segregation phenomenon of solid and liquid phases were discussed in this paper. Proper ranges of casting temperature and filling speed were obtained by the simulation. Good quality parts without shrinkage porosity were obtained in validation test using the casting temperature of 622~625°C and filling speed of 40mm/s. Rheocasting was an important forming method using semi-solid melt to manufacture metal parts directly. It was a promising trend of semi-solid forming industry which had shorter process, higher efficiency and lower energy consumption compared to SIMA method [1-4]. Rheocasting was generally applied to casting aluminum alloy but seldom to wrought aluminum alloys. The 7xxx series aluminum was generally manufactured though wrought or rolling technique to obtain dense parts with high strength. But few of them were produced directly through casting method without casting flaws[5-6].To process the 7xxx series aluminum by rheocasting method would further expand the application of wrought aluminum alloy, so it is essential to do some research on the rheocasting technique for wrought aluminum alloy. Taking the 7075 aluminum alloy as an example, this paper did some simulation work on temperature, flow field and shrinkage porosity distribution in the rheocasting process using the simulation casting software PROCAST. The effects of casting temperature and filling speed on the casting quality as well as the segregation phenomenon of solid and liquid phases were discussed in this paper. Proper ranges of casting temperature and filling speed were obtained by the simulation.

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