Effect of Annular Electromagnetic Stirring Process on Solidification Microstructure of 7075 Aluminium Alloy

2013 ◽  
Vol 652-654 ◽  
pp. 2418-2426 ◽  
Author(s):  
Zhi Hua Gao ◽  
Jun Xu ◽  
Zhi Feng Zhang ◽  
Meng Ou Tang
Keyword(s):  
Aluminum Alloy ◽  
Aluminium Alloy ◽  
Grain Refinement ◽  
Electromagnetic Stirring ◽  
7075 Aluminum Alloy ◽  
Pouring Temperature ◽  
Conventional Casting ◽  
Annular Gap ◽  
Solidification Microstructures ◽  
Gap Width

7075 aluminum alloy melt conditioned by annular electromagnetic stirring(A-EMS) was cast in the TP1 mould, and the effects of pouring temperature, stirring current, stirring frequency and annular gap width on microstructures were analyzed. The A-EMS process exhibits superior grain refinement and remarkable structure homogeneity compared with conventional casting(N-EMS) and conventional electromagnetic stirring casting(EMS). With the increasing of the pouring temperature, the microstructures of the sample conditioned by A-EMS are inclined to become coarse and non-uniform compared with which have the more serious inclination conditioned by N-EMS. With the stirring current or stirring frequency increasing, the rosette-like or dendritic primary α(Al) phase decreases significantly on the sample microstructures, and the non-dendritic primary α(Al) phase is finer and more spherical. Narrow annular gap is advantageous to obtain uniformly fine spherical solidification microstructures.

Effect of Melt Intensive Homogenization on Solidification Microstructure of 7075 Aluminium Alloy by Twin-Screw Stirring

2013 ◽  
Vol 750-752 ◽  
pp. 771-775
Author(s):  
Zhi Hua Gao ◽  
Jun Xu ◽  
Guo Jun Liu ◽  
Zhi Feng Zhang ◽  
Men Gou Tang ◽  
...  
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Grain Refinement ◽  
Size Dependence ◽  
Test Procedure ◽  
Standard Test ◽  
7075 Aluminum Alloy ◽  
Pouring Temperature ◽  
Screw Machine ◽  
Twin Screw

Intensive melt shearing achieved using a twin-screw machine was applied to the 7075 aluminum alloy melt to investigate its effects on grain refinement. Alloy melt without and with melt shearing was cast in the standard test procedure mould, and the effects of casting temperature, shearing time and shearing intensity on microstructures were analyzed. The results show that the intensive melt shearing exhibits superior grain refinement and remarkable structure homogeneity. Without shearing, the grain size increases significantly with the increase in pouring temperature, while with intensive melt shearing the grain size is finer at all the pouring temperatures tested with a reduced grain size dependence on the pouring temperature. With the shearing time or shearing intensity increasing, the grain size of the equiaxed primary α (Al) phase decreases on the sample microstructures, and the grain distributions trend to become more fine and non-dendritical.

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.

Combined Effect of Electromagnetic Field and Grain Refiner on Microstructure of Φ310 Mm 7050 Aluminium Alloy Ingot

2011 ◽  
Vol 399-401 ◽  
pp. 1708-1711 ◽  
Author(s):  
Yu Bo Zuo ◽  
Zhi Hao Zhao ◽  
Hai Tao Zhang ◽  
Ke Qin ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Field ◽  
Aluminum Alloy ◽  
Aluminium Alloy ◽  
Grain Refinement ◽  
Large Scale ◽  
Low Frequency ◽  
Combined Effect ◽  
Grain Refiner ◽  
Alloy Ingot ◽  
7050 Aluminum Alloy

Grain refinement is quite important for producing 7050 alloy ingot especially in large scale. Low frequency electromagnetic casting (LFEC) process was used to make 7050 aluminum alloy Φ310 ingots and study the effect of electromagnetic field and grain refiner on the microstructure of 7050 alloy ingots. The results showed that both grain refiner and low frequency electromagnetic field can result in some grain refinement of 7050 alloy. However, the low frequency electromagnetic field shows more remarkable grain refinement. For the grain refined alloy by grain refiner, further significant grain refinement can be achieved with the application of low frequency electromagnetic field. The finest microstructure was achieved by combining the applications of both grain refiner and electromagnetic field.

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.

Dynamic Recrystallization Microstructure Grain Size Prediction of 7075 Aluminum Alloy Piston Prepared by Isothermal Extrusion

2014 ◽  
Vol 1042 ◽  
pp. 81-86 ◽  
Author(s):  
Yue Wu ◽  
Wen Lin Chen ◽  
Yan Gao ◽  
Rui Zhou
Keyword(s):  
Grain Size ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Theoretical Calculation ◽  
Grain Refinement ◽  
Extrusion Process ◽  
7075 Aluminum Alloy ◽  
Lateral Extrusion ◽  
Element Simulation ◽  
Isothermal Extrusion

According to the structure features of the piston, the method of combining application of finite element simulation and theoretical analysis was explored to determine the extrusion process program and the extrusion process parameters. Theoretical calculation shows that a longitudinal extrusion and a lateral extrusion can form piston. The result comparing simulative prediction with theoretical calculation demonstrates that there is a good fit between the two and the theoretical calculation is right. The result of simulative prediction demonstrates that the grain size of piston after extrusion is about 17.8 μm and the refining rate reaches 55%. The grain size on both sides of the piston skirt and piston internal floor place is about 27 μm, so the refining effect is less obvious than other parts. However, the grain refinement in the piston pin holes is more obvious, the grain is refined to 13 μm and the refining rate is about 67.5%.The result comparing simulative prediction with the experimental analysis demonstrates that there is a good fit in grain refinement between the two.

J041031 Effect of high strength on grain refinement of 7075 aluminum alloy

2011 ◽  
Vol 2011 (0) ◽  
pp. _J041031-1-_J041031-5
Author(s):  
Yasuhiro KITANO ◽  
Masafumi NODA ◽  
Kunio FUNAMI
Keyword(s):  
Aluminum Alloy ◽  
Grain Refinement ◽  
High Strength ◽  
7075 Aluminum Alloy
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