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.

Preparation of Semi-Solid Billet with Less Liquid Content of 7A09 Aluminum Alloy by Partial-Melting Method

2009 ◽  
Vol 79-82 ◽  
pp. 1795-1798
Author(s):  
Wei Wei Wang ◽  
Jian Li Song ◽  
Jing Bo Yu
Keyword(s):  
Aluminum Alloy ◽  
Optical Microscopy ◽  
Partial Melting ◽  
Microstructure Evolution ◽  
Processing Parameters ◽  
Liquid Content ◽  
Melting Method ◽  
Wide Range ◽  
Fine Microstructure ◽  
Semi Solid

Preparation of semi-solid microstructure with less liquid content of 7A09 aluminum alloy industrial extrusion billets is studied in this paper. In the treatment, melting-stirring and predeformation of the alloy billets are not required. The influences of different heating temperatures and insulation time on the microstructure evolution are studied and the obtained microstructure is observed and analyzed by optical microscopy. 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. The liquid content can be controlled within a certain range.

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.

High Strain Rate Superplasticity in a Zr and Sc Modified 7075 Aluminum Alloy Produced by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 164-169 ◽  
Author(s):  
Krystof Turba ◽  
Premysl Malek ◽  
Edgar F. Rauch ◽  
Miroslav Cieslar
Keyword(s):  
Aluminum Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Rate Sensitivity ◽  
7075 Aluminum Alloy ◽  
Fine Grained ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Elongation To Failure

Equal-channel angular pressing (ECAP) at 443 K was used to introduce an ultra-fine grained (UFG) microstructure to a Zr and Sc modified 7075 aluminum alloy. Using the methods of TEM and EBSD, an average grain size of 0.6 1m was recorded after the pressing. The UFG microstructure remained very stable up to the temperature of 723 K, where the material exhibited high strain rate superplasticity (HSRSP) with elongations to failure of 610 % and 410 % at initial strain rates of 6.4 x 10-2 s-1 and 1 x 10-1 s-1, respectively. A strain rate sensitivity parameter m in the vicinity of 0.45 was observed at temperatures as high as 773 K. At this temperature, the material still reached an elongation to failure of 430 % at 2 x 10-2 s-1. These results confirm the stabilizing effect of the Zr and Sc additions on the UFG microstructure in a 7XXX series aluminum alloy produced by severe plastic deformation.

Experimental Research on Surface Roughness of Ultrasonic Assisted Grinding on 7075 Aluminum Alloy

2021 ◽  
Vol 1047 ◽  
pp. 62-67
Author(s):  
Shen Wang ◽  
Le Tong ◽  
Guang Jun Chen ◽  
Mao Xun Wang ◽  
Bin Dai ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Processing Parameters ◽  
7075 Aluminum Alloy ◽  
Machined Surface ◽  
Ultrasonic Assisted Grinding ◽  
Great Performance ◽  
Ultrasonic Assisted ◽  
Conventional Grinding ◽  
Micro Morphology

7075 aluminum alloy is widely used due to its great performance, especially in aerospace area. In this paper, ultrasonic-assisted grinding technology is used to process 7075 aluminum alloy. The data is obtained through experiments, and the surface roughness and morphology of ultrasonic assisted grinding and conventional grinding under different spindle speeds, feed rates, and amplitudes are analyzed. Research has found that the increase in spindle speed and amplitude will improve the quality of the machined surface and reduce the surface roughness by 82.1% and 36%. However, with the increase of feed rate, the surface quality decreased significantly, and the surface roughness increased by 55.6%. The surface micro-morphology of the machined workpiece is observed, and the effects of different processing parameters on the surface micro-morphology are obtained.

Microstructure Evolution and Coarsening Mechanism of 7075 Semi-Solid Aluminum Alloy Pre-Deformed by ECAP Method

2016 ◽  
Vol 256 ◽  
pp. 294-300 ◽  
Author(s):  
Jin Long Fu ◽  
Yu Wei Wang ◽  
Kai Kun Wang ◽  
Xiao Wei Li
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
Ostwald Ripening ◽  
Liquid Fraction ◽  
Isothermal Holding ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Semi Solid ◽  
Equiaxed Grains ◽  
Kinetics Of

To investigate the influence of refined grains on the microstructure of 7075 aluminum alloy in semi-solid state, a new strain induced melting activation (SIMA) method was put forward containing two main stages: pre-deformation with equal channel angular pressing (ECAP) method and isothermally holding in the semi-solid temperature range. The breaking up and growth mechanisms of the grains and kinetics of equiaxed grains coarsening during the semi-solid holding were investigated. The results showed that the average grain size after ECAP extrusion decreased significantly, e.g., microstructure with average globular diameter less than 5μm was achieved after four-pass ECAP extrusion. Obvious grain coarsening had been found during isothermal holding in the semi-solid state and the roundness of the grains increased with the increasing holding time. The proper microstructure of 66.8μm in diameter and 1.22 in shape factor was obtained under proper soaking condition (at 590°C for 15 min). Two coarsening mechanisms, namely, coalescence in lower liquid fraction and Ostwald ripening in higher liquid fraction contributed to the grain growth process.

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.

Investigation of 2024 Aluminum Alloy Flange Semi-Solid Thixoforging by Changing Cavity

2013 ◽  
Vol 834-836 ◽  
pp. 425-431
Author(s):  
Zhi Ming Du ◽  
Jun Liu ◽  
Jia Hong Niu ◽  
Wang Qi Zhao ◽  
Sen Cong
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Theoretical Calculation ◽  
Influence Factors ◽  
Forming Limit ◽  
2024 Aluminum Alloy ◽  
Grain Sizes ◽  
Microstructure And Mechanical Properties ◽  
Fine Microstructure ◽  
Semi Solid

Microstructure and mechanical properties of 2024 aluminum alloy flange semi-solid thixoforging by changing cavity was investigated. Theoretical calculation and forming test were adopted to study the preparation of flange. It is concluded that the influence factors of forming limit of flanges are radical load P, friction τ and thickness t by theoretical calculation. The results show that it is uniform in the process of forming. Microstructure and mechanical properties of flange have been improved significantly with the increase of the radical load. Way of variable cavity realized the real plastic deformation, which results in high mechanical properties of flange. The flange could obtain fine microstructure with grain sizes of 20~30μm, tensile strength of 433MPa and elongation of 10.1%, with changing amount of 30MPa. The results indicate that the microstructure and mechanical properties could achieve forging requirement and be controlled using changing cavity.

scholarly journals Effect of Semi-Solid Processing on the Microstructure and Mechanical Properties of Aluminum Alloy Chips with Eutectic Mg2Si Intermetallics

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1414
Author(s):  
Yong Guk Son ◽  
Sung Soo Jung ◽  
Yong Ho Park ◽  
Young Cheol Lee
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Eutectic Reaction ◽  
Microstructural Analysis ◽  
Aluminum Matrix ◽  
Processing Parameters ◽  
Holding Time ◽  
Mg2si Phase ◽  
Microstructure And Mechanical Properties ◽  
Semi Solid

This study reports the microstructural changes and mechanical properties of high-strength aluminum alloy chips prepared in the semi-solid state at different temperatures, pressures, and holding times. In semi-solid processes, these processing parameters must be optimized because they affect the microstructure and mechanical properties of the chips. In microstructural analysis, these parameters clearly influenced the spheroidization of the aluminum matrix. The aluminum matrix was uniformly spheroidized after semi-solid processing, and the densities of the final samples increased with the holding time. After 30 min holding time at a given temperature, the density approached the theoretical density, but the compressive strength of the samples seriously deteriorated. Meanwhile, fracture surface investigation revealed a deformed Mg2Si phase, which is formed through a eutectic reaction. The strength of this phase significantly decreased after increasing the holding time of the semi-solid processing from 10 to 30 min. Therefore, deformation of the Mg2Si phase caused by diffusion of aluminum into this phase can be a key factor for the decrease in the mechanical properties of samples fabricated with 30 min holding time.

Sign in / Sign up

Export Citation Format

Share Document