scholarly journals Aging Behavior of Aluminum Alloy 6082 Subjected to Friction Stir Processing

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 337 ◽  
Author(s):  
Khaled Al-Fadhalah ◽  
Fahad Asi
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Aging Time ◽  
Friction Stir Processing ◽  
Aging Temperature ◽  
Friction Stir ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Equiaxed Grains ◽  
Electron Back Scattered Diffraction

The present work examined the effect of artificial aging on the microstructure, texture, and hardness homogeneity in aluminum alloy AA6082 subjected to friction stir processing (FSP). Aging was applied to FSP samples at three different temperatures (150 °C, 175 °C, and 200 °C) for a period of 1 h, 6 h, and 12 h. Microstructure analysis using optical Microscopy (OM) and Electron Back-Scattered Diffraction (EBSD) indicated that FSP produced fine equiaxed grains, with an average grain size of 6.5 μm, in the stir zone (SZ) due to dynamic recrystallization. Aging was shown to result in additional grain refinement in the SZ due to the occurrence of recovery and recrystallization with either increasing aging temperature and/or aging time. An optimum average grain size of 3–4 μm was obtained in the SZ by applying aging at 175 °C. This was accompanied by an increase in the fraction of high-angle grain boundaries. FSP provided a simple shear texture with a major component of B fiber. Increasing aging temperature and/or time resulted in the formation of recrystallization texture of a Cube orientation. In addition, Vickers microhardness was evaluated for the FSP sample, indicating a softening in the SZ due to the dissolution of the hardening precipitates. Compared to other aging temperatures, aging at 175 °C resulted in maximum hardness recovery (90 Hv) to the initial value of base metal (92.5 Hv). The hardness recovery is most likely attributed to the uniform distribution of fine hardening precipitates in the SZ when increasing the aging time to 12 h.

Effect of Artificial Aging Parametars on Tensile Strength and Microstructure of 7075 Aluminum Alloy

2020 ◽  
Vol 8 (4) ◽  
pp. 37-47
Author(s):  
Mohamad Yahya Nefawy ◽  
Mahmoud Al Asad
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Ultimate Tensile Strength ◽  
Aging Time ◽  
Aging Temperature ◽  
Artificial Aging ◽  
7075 Aluminum Alloy ◽  
Different Temperatures ◽  
Aluminum Alloy 7075

In this research, we studied the effect of change in artificial aging time and temperature on tensile strength and Microstructure for 7075 aluminum alloy, Where samples of aluminum alloy 7075 were treated with artificial aging at different temperatures are 120 ° C, 160 ° C and 200 ° C for 0.5, 1.5, 3, 18, 48 hours. When the 7075 aluminum alloy was artificially aged in of 120 ° C and 160 ° C, the values of ultimate tensile strength (UTS) of the alloy were higher than when it was aged in 200 ° C. By increasing of artificial aging time, the UTS of 7075 aluminum alloy increased, when the aging temperature was 120 ° C or 160 ° C, while the UTS decreased when the aging temperature was 200 ° C. This is due to changes in the microstructure, grain size, and precipitating phases such as MgZn2.

Effect of Artificial Aging Parametars on Tensile Strength and Microstructure of 7075 Aluminum Alloy

2020 ◽  
Vol 8 (4) ◽  
pp. 37-47
Author(s):  
Mohamad Yahya Nefawy ◽  
Mahmoud Al Asad
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Ultimate Tensile Strength ◽  
Aging Time ◽  
Aging Temperature ◽  
Artificial Aging ◽  
7075 Aluminum Alloy ◽  
Different Temperatures ◽  
Aluminum Alloy 7075

In this research, we studied the effect of change in artificial aging time and temperature on tensile strength and Microstructure for 7075 aluminum alloy, Where samples of aluminum alloy 7075 were treated with artificial aging at different temperatures are 120 ° C, 160 ° C and 200 ° C for 0.5, 1.5, 3, 18, 48 hours. When the 7075 aluminum alloy was artificially aged in of 120 ° C and 160 ° C, the values of ultimate tensile strength (UTS) of the alloy were higher than when it was aged in 200 ° C. By increasing of artificial aging time, the UTS of 7075 aluminum alloy increased, when the aging temperature was 120 ° C or 160 ° C, while the UTS decreased when the aging temperature was 200 ° C. This is due to changes in the microstructure, grain size, and precipitating phases such as MgZn2.

Creep Age Formability of Friction Stir Welded 2A12 Aluminum Alloy Structures

2013 ◽  
Vol 753-755 ◽  
pp. 145-148
Author(s):  
Da Hai Liu ◽  
Jun Chu Li ◽  
Chun Chang
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Aging Time ◽  
Aging Temperature ◽  
Welded Structures ◽  
Friction Stir ◽  
Forming Characteristics ◽  
Welding Joints ◽  
Creep Age Forming

To establish the efficacy of creep age forming of the integrally friction stir welded panels, feasibility experiments were first conducted on friction stir welded rib-web panels of 2A12 aluminum alloys by using a designed air-loading age forming setup, and then related forming characteristics were investigated by using a mechanical-loading setup on the samples with and without friction stir welding joints. Results show that good age-formability can be observed from friction stir welded rib-web parts after creep age forming. The surface springback of the integral parts decreases with increasing the aging time and temperature. For 2A12 aluminum alloy, under an aging temperature of 190°C, a relatively better forming effect and strength can be reached at an aging time of about 8h. Compared with the non-welded structures, the introduction of friction stir welding will inhibit forming rate and will shorten the time of creep age forming.

Improvement of Microstructure and Mechanical Properties of 7050-T7451 Aluminum by a Novel Double-Sided Friction Stir Processing

2016 ◽  
Vol 838-839 ◽  
pp. 385-391
Author(s):  
Wen Jing Yang ◽  
Ji Zhong Li ◽  
Xue Wen ◽  
Hua Ding
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Friction Stir Processing ◽  
Surface Friction ◽  
Alloy Sheet ◽  
Bottom Surface ◽  
Aluminum Alloy Sheet ◽  
Friction Stir ◽  
Average Grain Size ◽  
Double Surface

Recently, friction stir processing (FSP), as an effective tool, has been employed to modify microstructures and mechanical properties of metal sheet. A novel technique of double surface friction stir processing (FSP) was proposed in this study. A 7050-T7451 aluminum alloy sheet of 6.5mm in thickness was processed by FSP with 30% overlap in each side. The position deviation of the stir pin from the upper surface to the bottom surface is 35%. Significant grain refinement with an average grain size of 2.5μm from the as-received 50μm, can be obtained after double-sided FSP. In comparison with the conventional FSP, no HAZ (heat affected zone) or TMAZ (thermal mechanical affected zone) was formed between the adjacent stir zones of the aluminum alloy sheet. At a strain rate of 10-3 s-1, a maximum elongation of 29.8% and 327% in transverse direction of FSP passes have been achieved at room temperature and 400°C, respectively.

Microstructural Evolution of 7050 Aluminum Alloy Semisolid Billets Fabricated by RAP Process

2014 ◽  
Vol 217-218 ◽  
pp. 29-36 ◽  
Author(s):  
Ju Fu Jiang ◽  
Zhi Ming Du ◽  
Ying Wang ◽  
Shou Jing Luo
Keyword(s):  
Aluminum Alloy ◽  
Microstructural Evolution ◽  
Ostwald Ripening ◽  
Soaking Time ◽  
Isothermal Temperature ◽  
7050 Aluminum Alloy ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Equiaxed Grains ◽  
Grain Coalescence

In the present study, 7050 supplied in extruded state was heated to different temperatures below solidus or the semisolid state and microstructural evolution and coarsening were investigated. The results showed that complete recrystallisation only occurs after soaking for 5 minutes at 545°C, which is characterised by formation of a lot of fine equiaxed grains. RAP is suitable for fabricating high-quality semisolid billet of 7050 aluminum alloy with an average grain size ranging from 47.4 um to 70.5 um and a roundness ranging from 1.3 to 1.7. Grain growth occurs as the samples were soaked at 610°C and 615°Cfor prolonged soaking time. When the isothermal temperatures were 610°C and 615°C, the coarsening rate constants were 359.5μm3s-1 and 470.5μm3s-1, respectively, indicating an increase of coarsening rate constant (K) with the increasing isothermal temperature. Coarsening tends to occur via Ostwald ripening and coalescence. Ostwald ripening plays an important role during the whole coarsening process, but the grain coalescence only contributes to coarsening after soaking for 12 minutes. 625°C is an optimal temperature to keep cylinder shape of the sample due to collapse of the sample above this temperature, leading to difficult clamping.

scholarly journals The Effect of Friction Stir Processing (FSP) on the Microstructure and Properties of AM60 Magnesium Alloy

2016 ◽  
Vol 61 (3) ◽  
pp. 1555-1560 ◽  
Author(s):  
J. Iwaszko ◽  
K. Kudła ◽  
K. Fila ◽  
M. Strzelecka
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Friction Stir Processing ◽  
Structural Changes ◽  
Flow Line ◽  
Homogeneous Microstructure ◽  
X Ray ◽  
Friction Stir ◽  
Average Grain Size

Abstract The samples of the as-cast AM60 magnesium alloy were subjected to Friction Stir Processing (FSP). The effect of FSP on the microstructure of AM60 magnesium alloy was analyzed using optical microscopy and X-ray analysis. Besides, the investigation of selected properties, i.e. hardness and resistance to abrasion wear, were carried out. The carried out investigations showed that FSP leads to more homogeneous microstructure and significant grain refinement. The average grain size in the stirred zone (SZ) was about 6-9 μm. in the thermomechanically affected zone (TMAZ), the elongated and deformed grains distributed along flow line were observed. The structural changes caused by FSP lead to an increase in microhardness and wear resistance of AM60 alloy in comparison to their non-treated equivalents. Preliminary results show that friction stir processing is a promising and an effective grain refinement technique.

Microstructure and Mechanical Properties of Submerged Friction Stir Processing Mg-Y-Nd Alloy

2015 ◽  
Vol 816 ◽  
pp. 404-410 ◽  
Author(s):  
Geng Hua Cao ◽  
Da Tong Zhang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Grain Size ◽  
Friction Stir Processing ◽  
Optimal Parameter ◽  
Hardness Measurement ◽  
Cast Sample ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size

Mg-2.5wt%Y-4wt%Nd-0.5wt%Zr casting alloy was subjected to submerged friction stir processing (SFSP) with different rotation rates (ω) and travel speeds (υ). The influence of the ratio of ω/υ on the microstructure and mechanical properties of Mg-Y-Nd alloy was investigated in the present work by optical microscopy, scanning electron microscopy, transmission electron microscopy, tensile test and hardness measurement. The results showed that the average grain sizes of SFSP samples were significantly refined compared with as-cast sample, and the coarse net-shaped Mg12Nd phases which located at grain boundaries in as-cast sample were changed into small particles. The combined effect of grain refinement and uniform particles distribution was responsible for the enhancement of mechanical properties. The relative optimal parameter of 600 rpm/60 mm·min-1in this research obtained the finest grain size and the best mechanical properties, which were 1.1 μm for average grain size, 305 MPa for ultimate tensile strength and 22% for elongation, respectively.

A Numerical Model for Predicting the Zener-Hollomon Parameter in the Friction Stir Processing of AZ31B

2014 ◽  
Vol 783-786 ◽  
pp. 93-99 ◽  
Author(s):  
Ali H. Ammouri ◽  
Ali H. Kheireddine ◽  
Ramsey F. Hamade
Keyword(s):  
Grain Size ◽  
Friction Stir Processing ◽  
Large Degree ◽  
Element Model ◽  
Representative Point ◽  
State Variables ◽  
Hollomon Parameter ◽  
Friction Stir ◽  
Power Equation ◽  
Average Grain Size

Grain size determines to a large degree the mechanical properties of the friction stir processed (FSP) material. Developed in this work is a numerical (FEM) based-model for predicting values of the Zener-Hollomon parameter (Z-parameter) as function of input process parameters during friction stir processing of AZ31B. Prediction of Z values is desirable given that direct relations exist between the Z-parameter and the average grain size in the dynamically recrystallized zone (DRX). For this purpose, utilized in this work is a robust finite element model with a suitable constitutive equation and boundary conditions the results of which have been previously validated against published experimental data. A virtual test matrix constituting of 16 cases (4 spindle speed, N, x 4 feed, f) was run. Based on resulting state variables of strain rates and temperatures at a representative point within the stir zone, a statistically-validated power equation model was developed that relates Z-parameter values to input parameters of speed and feed. The results of the numerically developed power equation were validated against experimental results. This model can be readily used in future control frameworks to FSP produce AZ31B sheets of a predefined target grain size.

Microstructure Control and Mechanical Properties of Multipass Friction Stir Processed High Strength Aluminum Alloy

2012 ◽  
Vol 735 ◽  
pp. 316-321 ◽  
Author(s):  
Yutaka Matsuda ◽  
Goroh Itoh ◽  
Yoshinobu Motohashi
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Base Metal ◽  
Friction Stir Processing ◽  
Superplastic Deformation ◽  
High Strength ◽  
7075 Aluminum Alloy ◽  
Friction Stir ◽  
High Strength Aluminum Alloy ◽  
Equiaxed Grains

Friction stir processing (FSP) causes fine-equiaxed microstructure[1]. In this study, microstructure and mechanical properties of a 7075 aluminum alloy subjected to multipass FSP, MP-FSP, are assessed. A new zone, PBZ, has been discovered between stir zones, SZs. The SZs are composed of fine-equiaxed grains, while PBZs are composed of two types of (fine-equiaxed and coarse-elongated) grains, both of which are still finer than those of base metal. Elongation at 773K of MP-FSPed specimen becomes larger than that of base metal, based on superplastic deformation due to the finer microstructure. Local elongation is smaller in PBZ than in SZ.

scholarly journals A Physical-Based Plane Stress Constitutive Model for High Strength AA7075 under Hot Forming Conditions

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 314
Author(s):  
Fulong Chen ◽  
Haitao Qu ◽  
Wei Wu ◽  
Jing-Hua Zheng ◽  
Shuguang Qu ◽  
...  
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Plane Stress ◽  
Metal Forming ◽  
Electron Backscatter Diffraction ◽  
High Strength ◽  
Material Model ◽  
Hot Forming ◽  
Industrial Processing ◽  
Average Grain Size

Physicallybased constitutive equations are increasingly used for finite element simulations of metal forming processes due to the robust capability of modelling of underlying microstructure evolutions. However, one of thelimitations of current models is the lack of practical validation using real microstructure data due to the difficulties in achieving statistically meaningful data at a sufficiently large microstructure scale. Particularly, dislocation density and grain size governing the hardening in sheet deformation are of vital importance and need to be precisely quantified. In this paper, a set of dislocation mechanics-based plane stress material model is constructed for hot forming aluminum alloy. This material model is applied to high strength 7075 aluminum alloy for the prediction of the flow behaviorsconditioned at 300–400 °C with various strain rates. Additionally, an electron backscatter diffraction (EBSD) technique was applied to examine the average grain size and geometrical necessary dislocation (GND) density evolutions, enabling both macro- and micro- characteristics to be successfully predicted. In addition, to simulate the experienced plane stress states in sheet metal forming, the calibrated model is further extended to a plane stress stateto accuratelypredict the forming limits under hot conditions.The comprehensively calibrated material model could be used for guidinga better selection of industrial processing parameters and designing process windows, taking into account both the formed shape as well as post formed microstructure and, hence, properties.

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