A Study on the Nucleation Mechanism of Nano-Scale Precipitates of 7055 Aluminum Alloy

NANO ◽  
2017 ◽  
Vol 12 (12) ◽  
pp. 1750147
Author(s):  
Ping Zhang ◽  
Youqiang Wang
Keyword(s):  
Solid Solution ◽  
Aluminum Alloy ◽  
Microstructural Evolution ◽  
Solution Treatment ◽  
Age Hardening ◽  
Orientation Relation ◽  
Nucleation Mechanisms ◽  
The Matrix ◽  
7055 Aluminum Alloy ◽  
Al Matrix

7055 aluminum alloy is a typical age-hardening alloy whose properties change with microstructural evolution as a result of heat treatment. In this paper, the microstructural evolution of the alloy after solid solution treatment and manual aging is examined using SEM, TEM and HADDF. The precipitation, nucleation and growth mechanisms of [Formula: see text] and [Formula: see text] phases are also analyzed. Results show that, as aging proceeds, the Al–Cu phase gradually enlarges and thickens the following precipitation sequence of supersaturated solid solution (SSSS) [Formula: see text] GPI zone [Formula: see text] GPII zone [Formula: see text] phase [Formula: see text] phase; some [Formula: see text] phases formed during aging, which have two different nucleation mechanisms: homogeneous nucleation and heterogeneous nucleation, the [Formula: see text] phases of the latter being marginally larger in size than those of the former. There is a transition in the transformation of (Al3Cu) in GPII zone into [Formula: see text]-phase (Al2Cu). The orientation relation between [Formula: see text] phase and Al matrix is (100)Al//(100)[Formula: see text], (010)Al//(010)[Formula: see text], (001)Al//(001)[Formula: see text]. According to this relationship, [Formula: see text] phase has three variants in the matrix: Variants 1, 2, and 3, which represent the [Formula: see text] phase along {100}Al, {010}Al and {001}Al. As [Formula: see text] phase has a special orientation relation with Al matrix (100)Al//(100)[Formula: see text], (010)Al//(010)[Formula: see text], (001)Al//(001)[Formula: see text], [Formula: see text] phase is distributed in disc form on {001}Al. Significantly larger [Formula: see text] phase can be observed. The orientation relation between S phase and Al matrix is [100]Al//[100]S, [021]Al//[010]S, [012]Al//[001]S. [Formula: see text] phase grows in step form for a period equaling to 1.75-fold unit cell of [Formula: see text]. As [Formula: see text] phase grows, the Cu atoms segregated on the edge of [Formula: see text] phase are gradually consumed.

The Effects of Solid-Solution on Properties and Microstructure of 6063 Aluminum Alloy

2014 ◽  
Vol 881-883 ◽  
pp. 1346-1350 ◽  
Author(s):  
Ben Chen ◽  
Yu Jiao Wu ◽  
Tao Zhu ◽  
Xin Yun Li
Keyword(s):  
Solid Solution ◽  
Electrical Resistivity ◽  
Aluminum Alloy ◽  
Solution Process ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Solution Treated ◽  
Suitable Solution ◽  
6063 Aluminum Alloy

The solution treatment of 6063 aluminum alloy was carried out and the influences of solution process on microstructure, strength, hardness, and electrical resistivity of 6063 aluminum alloy was analyzed. The result shows that the suitable solution treatment can improve alloy solution-degree fully, meanwhile the changes of electrical resistivity of alloy tend to be balanced. The suitable solution process for 6063 aluminum alloy is solution-treated at 520°C for 3.5h, and the strength and hardness of alloy can be enhanced extremely after aging-treatment at 200°C for 5h.

Influences of the γ′ Phase on the Mechanical Properties of a Nickel-Based Single Crystal Superalloy

2021 ◽  
Vol 1023 ◽  
pp. 45-52
Author(s):  
Xiao Yan Wang ◽  
Meng Li ◽  
Zhi Xun Wen
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Single Crystal ◽  
Tensile Properties ◽  
Room Temperature ◽  
Solution Treatment ◽  
Single Crystal Superalloy ◽  
Original Material ◽  
Solid Solution Treatment ◽  
The Matrix

After solid solution treatment at 1335°C for 4 hours and cooling to room temperature at different rate, the nickel-based single crystal superalloy were made into three kinds of nickel-based single crystal superalloy materials containing different size γ′ phases, respectively. The tensile test of I-shaped specimens was carried out at 980°C, and their effect of γ′ phase microstructure on the tensile properties was studied. The results show that the yielding strength of the material air-cooled to room temperature was lower than that with cooling rate at 0.15°C/s, but both of them were lower than the yielding strength of original material. Little difference was found on the elastic modulus of I-shaped specimens made of three kinds of materials. When the cubic degree of the γ′ phase is higher and the size is larger, the tensile properties of the material is better, which can be attributed to the larger size and narrower channel of the matrix phase that lead to higher dislocation resistance.

Effect of Solid Solution Treatment on the Microstructure and Mechanical Properties of IN738LC Superalloy

2011 ◽  
Vol 378-379 ◽  
pp. 744-747 ◽  
Author(s):  
Jeong Min Kim ◽  
Joon Sik Park ◽  
Ho Seob Yun ◽  
Seung Jin Lee ◽  
Seong Uk An
Keyword(s):  
Solid Solution ◽  
Size Distribution ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Solution Treatment Temperature ◽  
Gamma Prime ◽  
Solid Solution Treatment ◽  
Treatment Conditions ◽  
The Matrix ◽  
Single Size

Cast IN738LC alloy mainly consists of primary gamma matrix, gamma prime precipitates, and carbides. SEM-EDS analysis results suggested that most of the carbides are MC type ones that possess high Ti or Ta contents. MC carbides were partly dissolved into the matrix during the solid solution treatment, and the morphology and size of carbides were influenced by the solid solution treatment temperature. Characteristics of gamma prime precipitates were also significantly affected by the solid solution treatment conditions. Single or duplex size distributions of gamma prime precipitates were obtained depending on the solid solution treatment condition. Higher tensile strength was obtained in the case of finer precipitation size and in the case of single size distribution as compared with that of duplex size distribution.

Study on Microstructure and Property of Al-Si-Cu-Mg Casting Alloy during Solution and Aging Treatment

2014 ◽  
Vol 915-916 ◽  
pp. 650-653
Author(s):  
Li Jun Wei ◽  
Bo Long Li ◽  
Liu Yi Guan ◽  
Zuo Ren Nie
Keyword(s):  
Solid Solution ◽  
Artificial Aging ◽  
Treatment Process ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Solution Time ◽  
Casting Alloy ◽  
The Matrix ◽  
Optimum Heat ◽  
Optimum Heat Treatment

The effect of the alloying elements Cu and Mg, the solution and artificial aging process on the microstructure and property were investigated. Solution treatment was carried out at 535 ± 5°C in different time for the Al-Si-Cu-Mg casting alloy, and the artificial aging was carried out at 160 ± 5°C and 175 ± 5°C and190 ± 5°C in different time. The microstructure has been investigated by Optical Microscopy, Scanning Electron Microscopy (SEM). We found that most of Cu and Mg element in the alloy gathered and formed multivariate composite phase at grain boundaries. With the increasing of solid solution time, the intermetallic phases will be dissolution into the matrix, and if the solid solution time is long enough, they will be distributed uniformly in alloy. With the increase of the aging temperature, the time for aging peak will be shorter, but the peak will be lower. Finally, we determine the optimum heat treatment process is 535°C × 12h + 175°C × 8h。

Semisolid Microstructural Evolution of Equal Channel Angular Extruded Mg-Al Alloy During Partial Remelting

2008 ◽  
Vol 141-143 ◽  
pp. 557-562 ◽  
Author(s):  
S.M. Liang ◽  
Rong Shi Chen ◽  
En Hou Han
Keyword(s):  
Solid Solution ◽  
Microstructural Evolution ◽  
Equal Channel Angular Extrusion ◽  
Isothermal Holding ◽  
Solution Treatment ◽  
Solid Particles ◽  
Al Alloy ◽  
Semisolid State ◽  
Effects Of Temperature ◽  
Spherical Grains

Using equal channel angular extrusion (ECAE) process, which combine the advantages of grain refinement and induced strain, for preparing semisolid billets is a relatively new Strain Induced Melt Activation(SIMA)method. This paper investigates the remelting and semisolid isothermal holding behavior of Mg-9Al alloy after ECAE processing at 350°C. It has been found that 2 passes ECAE-ed billets are qualified for obtaining spherical grains after remelting and isothermal holding treatment. Increasing the ECAE process from 2 passes to 8 passes has no further significant effects on the size and roundness of the solid particles at the semisolid state. The effects of temperature and isothermal holding time on microstructural evolution have also been investigated. In addition, the solid solution treatment before the ECAE processing affected greatly on microstructural evolution of the alloy during ECAE processing and thus the following remelting and isothermal holding behavior. The Mg17Al12 precipitates were uniformly decomposed from the saturated solid solution in the solutionized samples during ECAE processing. The coalescence of grains together with the self-blocking effect generated more entrapped liquid in the solutionized sample at semisolid state. Moreover, the solid particles of solutionized samples have bigger size and grow faster, which are detrimental to SSM processability.

Effect of Impact Compression on Age Hardening Behavior of Aluminum Alloys

2014 ◽  
Vol 566 ◽  
pp. 409-414 ◽  
Author(s):  
Yuki Kitani ◽  
Keitaro Horikawa ◽  
Hidetoshi Kobayashi ◽  
Kenichi Tanigaki ◽  
Tomo Ogura ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Aging Time ◽  
Point Defects ◽  
Solution Treatment ◽  
Age Hardening ◽  
Impact Compression ◽  
6061 Aluminum Alloy ◽  
Hardening Behavior ◽  
The Impact

The effect of impact compression on age hardening behavior was examined for Meso20 and 6061 aluminum alloys using a single stage gun. The hardness of Meso20 and 6061 aluminum alloy applied with an impact compression (about 5.0GPa) after the solution treatment increased with the aging time. The cluster of point defects like stacking fault tetrahedral (SFT) was observed in the 6061 aluminum alloys with the impact compression (5.3GPa) after the solution treatment. Even after the impact compression, distribution of the aging precipitates was clearly identified.

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