Effects of Various Cooling Techniques on Grain Refinement of Aluminum 7075-T651 During Friction Stir Processing

2016 ◽  
Author(s):  
Vivek V. Patel ◽  
Vishvesh J. Badheka ◽  
Samarth R. Zala ◽  
Sagar R. Patel ◽  
Utsav D. Patel ◽  
...  
Keyword(s):  
Grain Size ◽  
Friction Stir Processing ◽  
Weight Ratio ◽  
Optical Microscope ◽  
Process Temperature ◽  
Friction Stir ◽  
Fine Grain ◽  
State Process ◽  
Structural Applications ◽  
Aluminum 7075

Aluminum 7075 alloy (AA 7075) is one of the prime materials used in the aviation and automotive industry because of its high strength to weight ratio, good amount of fatigue strength and high machinability. Friction stir processing (FSP) is one of the emerging solid state process that refines the microstructure and hence improved mechanical properties are obtained. The process temperature during FSP affects the resulting microstructure so the attempt for reducing the process temperature can result into reduction in the grain size. The fine grain size microstructure delivers high percentage of elongation which reduces the number of joints and welds in the critical structural applications. So, by implementing coolants such as water and carbon dioxide (CO2) during this process had hindered the grain growth and very fine grained microstructure was obtained. The fine grain microstructure offers higher elongation and hardness as deformation starts from the grain boundaries. In this experimental investigation we intended to keep the temperature generation during the process as low as possible by keeping the process parameters of 765 rpm, 31.5 mm/min fees rate and 20 tilt of the tool (optimized for tapered threaded cylindrical pin tool) constant. All the samples were examined by metallographic characterization using optical microscope. The grain size measurements for all three FSP samples were carried out. Water and CO2 cooled FSP samples reported much more fine grain as compared to naturally cooled sample because of the less heat input during the process.

scholarly journals The Role of Friction Stir Processing (FSP) Parameters on TiC Reinforced Surface Al7075-T651 Aluminum Alloy

2016 ◽  
Vol 21 (4) ◽  
pp. 508-516 ◽  
Author(s):  
Felipe García-Vázquez ◽  
Benjamín Vargas-Arista ◽  
Rodrigo Muñiz ◽  
Juan Carlos Ortiz ◽  
Héctor Hernández García ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Friction Stir Processing ◽  
Weight Ratio ◽  
Nano Particles ◽  
Friction Stir ◽  
Surface Composite ◽  
Surface Composites ◽  
Structural Applications ◽  
Composite Distribution

Abstract: Aluminum alloys are very promising for structural applications in aerospace, military and transportation industries due to their light weight, high strength-to-weight ratio and excellent resistance to corrosion. In comparison to unreinforced aluminum alloys, aluminum/aluminum alloy matrix composites reinforced with ceramic phases exhibit higher strength and hardness, improved tribological characteristics. A novel surface modifying technique, friction stir processing (FSP), has been developed for fabrication of surface composite with an improved performance. The effect of FSP parameters such as number of passes, direction of each pass, sealed or unsealed groove on microstructure was investigated. In this work, nano-particles of TiC (2% in weight) were added to aluminum alloy AA7075-T651 to produce a functional surface. Fixed parameters for this AA7075 alloy were used; rotation speed of 1000 rpm, travel speed of 300 mm/min and pin penetration of 2.8 mm. Optical microscopy (OM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to study the microstructure of the fabricated surface composites. The results indicated that the selected FSP parameters influenced the area of surface composite, distribution of TiC particles and micro-hardness of the surface composites. Finally, in order to evaluate rate wear the pin on disk test was carried out.

Dispersion of Al2O3 Reinforcements in Al Composites via Friction Stir Processing

2016 ◽  
Vol 861 ◽  
pp. 236-240 ◽  
Author(s):  
Zheng Lin Du ◽  
Ming Jen Tan ◽  
Jun Feng Guo ◽  
Jun Wei
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Solid State ◽  
Friction Stir Processing ◽  
Micro Hardness ◽  
Friction Stir ◽  
Grain Sizes ◽  
State Process ◽  
Uniform Dispersion ◽  
Disperse Reinforcement

Friction Stir Processing is a solid state process with the ability to modify microstructure and refine grain sizes of the material without melting and uniformly disperse reinforcement particles in the material matrix resulting in further improvements in the mechanical properties. In this study, it was used to disperse Al2O3 reinforcement particles of different sizes. Uniform dispersion of the reinforcements was achieved in the aluminium matrix with significant reduction in grain size were observed via SEM and EBSD. Improvement in Vicker’s micro hardness was observed after FSP.

Ultra Fine Grain via Friction Stir Processing of 7075-T6 Grade Aluminum Alloy

2010 ◽  
Vol 297-301 ◽  
pp. 1116-1121
Author(s):  
M. Esmaily ◽  
Ali Shokuhfar
Keyword(s):  
Grain Size ◽  
Friction Stir Processing ◽  
Research Work ◽  
Stir Zone ◽  
Friction Stir ◽  
Aluminum Sheets ◽  
Fine Grain ◽  
Structural Evaluation ◽  
Transmission Electron ◽  
20 Nm

In this research work, characterization of a broad area zone with ultra fine grain size of 7075-T6 grade aluminum sheets with the thickness of 8 mm was carried out using friction stir processing (FSP) and quenching by liquid nitrogen on both, i.e. upper and lower, surfaces. In the first step, ability and competence of two tools with different designs in creating a stir zone without any defects were examined; selected samples were exposed to FSP by efficient tools and in a highly extensive quenching media. Friction stir processing was carried out on the samples in three different rates (fast, medium and slow), the mechanism of ultra fine grain size as well as the creation of dislocation in thermo-mechanical affected zone was evaluated. Micro structural evaluation using transmission electron microscopy showed that the samples exposed to FSP in slow manner, had the finest grain size (20 nm) in the stir zone, and the lowest amount of dislocation in the thermo-mechanical affected zone. More details are discussed in the presented results.

A Novel Way to Fabricate Carbon Nanotubes Reinforced Copper Matrix Composites by Friction Stir Processing

2011 ◽  
Vol 391-392 ◽  
pp. 524-529 ◽  
Author(s):  
Wen Liang Chen ◽  
Chun Ping Huang ◽  
Li Ming Ke
Keyword(s):  
Carbon Nanotubes ◽  
Grain Size ◽  
Friction Stir Processing ◽  
Copper Matrix ◽  
Parent Material ◽  
Experimental Results ◽  
Matrix Composites ◽  
Small Decrease ◽  
Copper Matrix Composites ◽  
Friction Stir

Carbon nanotubes(CNTs) reinforced copper matrix composites were successfully produced by Friction Stir Processing (FSP). The effect of applying multiple FSP passes on the forming of composites was studied, the microstructure, microhardness and conductivity of the good forming composite were analyzed. The experimental results showed that CNTs uniformly distributed and good forming composite can be obtained by three FSP passes. Compared to the parent material, the grain size of the composite has significantly refined, and the microhardness of the composite has also greatly improved, but the conductivity of the composite has a small decrease.

scholarly journals Microstructure and Mechanical Properties of 34CrNiMo6 Steel Repaired by Friction Stir Processing

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 279 ◽  
Author(s):  
Zhongwen Wu ◽  
Chunping Huang ◽  
Fencheng Liu ◽  
Chun Xia ◽  
Liming Ke
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Processing ◽  
Steel Structures ◽  
Optical Microscope ◽  
Filling Material ◽  
Welding Wire ◽  
Friction Stir ◽  
Filling Materials ◽  
Microstructure And Mechanical Properties ◽  
34Crnimo6 Steel

Repairing damaged parts using proper repairing methods has become an important means to reduce manufacturing and operational costs and prolong the service life of 34CrNiMo6 steel structures. In the conventional fusion repairing method, welding wire and powder are often used as filling materials. Filling materials are often expensive or difficult to find. Some metallurgical issues (such as solidification crack, higher distortion) were also found with these methods. At the same time, most of the equipment that requires welding wire and powder is expensive. In this study, a new method based on friction stir processing (FSP) was successfully employed to repair 34CrNiMo6 steel, using a block as filling material. Filling blocks are much cheaper than conventional fusion repair consumables. As a result of solid-state repair, this method can also avoid the metallurgical issues of fusion repair. The microstructure and mechanical properties of the repaired samples were investigated using OM (Optical Microscope), SEM, EDS (Energy Dispersive Spectroscopy), XRD, and a Vickers hardness electronic universal tensile tester. The results showed that 34CrNiMo6 steel was successfully repaired by this method, with no defect. Tensile tests showed that the maximum ultimate strength (UTS) was 900 MPa and could reach 91.8% of that of the substrate. The fracture mode of the tensile samples was ductile/brittle mixed fracture. Hence, the repairing method based on FSP appears to be a promising method for repairing castings.

Effect of Friction Stir Processing Parameters on the Properties of AA7075-T73/Al2O3 Surface Metal Matrix Composite

2020 ◽  
Vol 1002 ◽  
pp. 140-150
Author(s):  
Ali H. Al-Helli ◽  
Ahmed R. Alhamaoy ◽  
Ayad Murad Takhakh
Keyword(s):  
Friction Stir Processing ◽  
Particle Distribution ◽  
Surface Hardness ◽  
Base Material ◽  
Processing Parameters ◽  
Optical Microscope ◽  
Friction Stir ◽  
Surface Composite ◽  
Surface Metal ◽  
Number Of Passes

Friction Stir Processing (FSP) technology was wielded to output the Al7075/ Al2O3 surface composite. The effects parameters of processing method on particle distribution have been studied. The microstructure and mechanical characteristics of the samples were examined using the optical microscope, SEM and hardness examination. Acquired consequences, showed that Al2O3 particles were in a good interior distribution inside the basement. This technique produced excellent bonding between the surface composite and the base material. On other hand the surface hardness was increased about 25% as compared with the substrate. In addition, grain matrix refinement and enhanced particle distribution were obtained after each FSP pass. Also the dispersion of Al2O3 particles in the stirred area became more homogeneous and the average hardness improved by increasing the number of passes.

Pre-cooling Effects on the Resulting Grain Size in Friction Stir Processing of AZ31B

2015 ◽  
pp. 355-365
Author(s):  
Ali H. Ammouri ◽  
Ghassan T. Kridli ◽  
George Y. Ayoub ◽  
Ramsey F. Hamade
Keyword(s):  
Grain Size ◽  
Friction Stir Processing ◽  
Friction Stir ◽  
Cooling Effects

Corrosion Resistance of Friction Stir Processed AZ91D Magnesium Alloy under a Salt Fog Environment

2015 ◽  
Vol 787 ◽  
pp. 426-430 ◽  
Author(s):  
Jason Christopher Jolly ◽  
V. Karthik Srinivas ◽  
A.K. Lakshminarayanan
Keyword(s):  
Corrosion Resistance ◽  
Solid State ◽  
Friction Stir Processing ◽  
Salt Spray ◽  
Friction Stir ◽  
State Process ◽  
Processing Techniques ◽  
Micro Analysis ◽  
Equiaxed Grains ◽  
Salt Fog

Magnesium alloys are widely used in applications where weight reduction is of primary importance. MgAZ91D is an Mg-Al-Zn alloy and its application in the automotive sector is limited by its poor corrosion resistance. Recent advances in solid state processing techniques have made it easier to modify the mechanical and corrosion characteristics of various alloys. Friction stir processing (FSP) is such a solid-state process for surface and sub-surface modification, which increases the microstructural densification, thereby producing fine and equiaxed grains. Through this work, an attempt was made to analyse the effect of friction stir processing on the corrosion resistance of the alloy in an enclosed salt spray chamber. Micro-analysis tools like FESEM and EDS are used to supplement our results. It is seen that, FSP significantly contributes to the increase in the corrosion resistance by homogenising the distribution of α and β phases and hence making the use of the alloy more practical in moisture rich environments.

Spiral Friction Stir Processing (SFSP) for the Extrusion of Lightweight Alloy Tubes

2012 ◽  
Author(s):  
Fadi Abu-Farha
Keyword(s):  
Friction Stir Processing ◽  
Special Form ◽  
Bulk Material ◽  
Processing Technique ◽  
Grain Structure ◽  
The Novel ◽  
Friction Stir ◽  
Fine Grain ◽  
Processed Material ◽  
Novel Concept

While friction stir processing (FSP) has been used to refine the grain structure in sheet metals, this work explores the potentials of refining the grain structure of bulk material using the friction stirring phenomenon via the novel concept of spiral friction stir processing (SFSP). With this concept, the rotating stirring tool is plunged into the material, rather than being traversed across it as in FSP; this imposes severe plastic deformation on the material while pushing it radially outwards in complex spiral paths. By confining the material within a closed cylindrical die, the processed material is microstructurally-refined while forming a tube via a special form of SFSP called “friction stir back extrusion” (FSBE). The hypothesised concept was investigated using samples from the AA6063-T52 aluminium alloy and the AZ31B-F magnesium alloy. The preliminary results presented here demonstrate the viability of SFSP, and the special form of FSBE, in producing tubular samples that are structurally sound, with no signs of voids or internal channels. Optical microscopy was performed at key locations within selected tube specimens, and the obtained micrographs clearly show the presence of a stir zone with a fine grain structure; grain size measurements demonstrate the effectiveness of the processing technique in refining the microstructure of the starting material.

scholarly journals Friction Stir Processing of the Magnesium Alloy AZ61: Grain Size Refinement and Mechanical Properties

2012 ◽  
Vol 706-709 ◽  
pp. 1823-1828 ◽  
Author(s):  
J.A. del Valle ◽  
P. Rey ◽  
D. Gesto ◽  
D. Verdera ◽  
Oscar A. Ruano
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Friction Stir Processing ◽  
Superplastic Forming ◽  
Important Change ◽  
Heat Extraction ◽  
Processing Temperature ◽  
Friction Stir ◽  
Size Refinement

The effect of friction stir processing (FSP), on the microstructure and mechanical properties of a magnesium alloy AZ61 has been analyzed. This is a widely used wrought magnesium alloy provided in the form of rolled and annealed sheets with a grain size of 45 μm. The FSP was performed with an adequate cooling device in order to increase the heat extraction and reduce the processing temperature. The final microstructure showed a noticeable grain size refinement down to values close to 1.8 μm and an important change in texture. The change in texture favors basal slip during tensile testing leading to an increase of ductility and a decrease in yield stress. The stability of the grain size and the creep behavior at high temperatures were investigated. The optimum conditions for superplastic forming were determined; however, the presence of a large amount of cavities precludes the achievement of high superplastic elongations. Additionally, these results are compared with those obtained by severe hot rolling.

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