Simulation of Friction Stir Processing with Internally Cooled Tool

2012 ◽  
Vol 445 ◽  
pp. 560-565
Author(s):  
A.N. Albakri ◽  
B. Mansoor ◽  
H. Nassar ◽  
M.K. Khraisheh
Keyword(s):  
Grain Refinement ◽  
Friction Stir Processing ◽  
Three Dimensional ◽  
Excessive Heat ◽  
Friction Stir ◽  
Processed Material ◽  
Internally Cooled ◽  
Division Process ◽  
Tool Cooling ◽  
Temperature Levels

Friction stir processing (FSP) is considered to be a promising sustainable technique for grain refinement of metallic alloys. The heat generated during FSP promotes dynamic recrystallization in processed material which is essential for grain sub-division process. However, excessive heat generation can lead to high temperatures of >300°C that may cause abnormal grain growth in the processed material. On the other hand, repetitive high temperature heating cycles can reduce the lifetime of the FSP tool. Therefore, it is essential to manage the process heat not only to achieve homogeneity and finer grain sizes in the processed material but also to reduce tool wear. In this work, friction stir processing of AZ31B Mg with an internally cooled FSP tool is simulated by a three-dimensional CFD model. We have studied the effect of rapid tool cooling on temperature and flow stress distribution in processed material. Additionally, the grain size and hardness of the processed material is estimated by using Zener-Holloman and Hall-Petch based relationships. It was found that FSP with internally cooled tool is a promising approach that effectively controls temperature levels during processing. Therefore it enables the achievement of better mechanical properties by effective grain refinement and has a positive effect on tool life.

Influence of Process Parameters on Microstructure of Friction Stir Processed Mg AZ31 Alloy

2017 ◽  
pp. 1293-1305
Author(s):  
G. Venkateswarlu ◽  
M.J. Davidson ◽  
G.R.N. Tagore ◽  
P. Sammaiah
Keyword(s):  
Plastic Deformation ◽  
Grain Refinement ◽  
Process Parameters ◽  
Tilt Angle ◽  
Friction Stir Processing ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Homogeneous Microstructure ◽  
Friction Stir ◽  
Tool Tilt Angle

Friction stir processing (FSP) has been developed on the principles of friction stir welding (FSW) as an effective and efficien new method for grain refinement and microstructural modification, providing intense plastic deformation as well as higher strain rates than other conventional severe plastic deformation methods. FSP produces an equiaxed homogeneous microstructure consisting of fine grains, resulting in the enhancement of the properties of the material at room temperature. The objective of the present paper is to examine the influence of friction stir processing (FSP) parameters namely tool rotational speed (RS), tool traverse speed (TS) and tool tilt angle (TA) on the microstructures of friction stir processed AZ31B-O magnesium alloy. This investigation has focused on the microstructural changes occurred in the dynamically recrystallised nugget zone/ stir zone and the thermo mechanically affected zone during FSP. The results presented in this work indicate that all the three FSP process parameters have a significant effect on the resulting microstructure and also found that the rotational speed has greatly influenced the homogenization of the material. The grain refinement is higher at intermediate rotational speed (1150 rpm), traverse speed (32 mm / min and tilt angle (10). It is established that FSP can be a good grain refinement method for improving the properties of the material.

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.

Effect of tool velocity ratio on tensile properties of friction stir processed aluminum based metal matrix composites

2016 ◽  
Vol 25 (3-4) ◽  
pp. 99-109 ◽  
Author(s):  
P. Vijayavel ◽  
V. Balasubramanian
Keyword(s):  
Tensile Properties ◽  
Heat Generation ◽  
Metal Matrix ◽  
Velocity Ratio ◽  
Microstructural Characterization ◽  
Traverse Speed ◽  
Matrix Composites ◽  
Excessive Heat ◽  
Friction Stir ◽  
Processed Material

AbstractIn friction stir processing (FSP), tool rotational speed (TRS) and tool traverse speed (TTS) are the two important parameters, known to produce significant changes in the properties of the processed material. Increasing the TRS and TTS beyond a certain level would produce undesirable results. The heat generation will increase with an increase in the TRS and decrease in TTS. Excessive heat generation results in the formation of coarse grains exhibiting poor mechanical properties. The heat generation will decrease with decrease in the TRS and increase in TTS. Low heat generation will lead to inadequate plasticization and improper material flow. Hence a perfect combination of TRS and TTS is required to attain desirable properties in FSPed material. In this investigation FSP was carried out on aluminum based metal matrix composite (LM25AA+5%SiCp) material using five different tool velocity ratios (TVR: TRS/TTS). The FSP was subjected to microstructural characterization and tensile properties, evaluation. The results revealed that the TVR of 2.6 yielded superior tensile properties compared to other conditions.

scholarly journals Mg/ZrO2 Metal Matrix Nanocomposites Fabricated by Friction Stir Processing: Microstructure, Mechanical Properties, and Corrosion Behavior

2021 ◽  
Vol 9 ◽  
Author(s):  
Ke Qiao ◽  
Ting Zhang ◽  
Kuaishe Wang ◽  
Shengnan Yuan ◽  
Shengyi Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Grain Refinement ◽  
Friction Stir Processing ◽  
Biological Properties ◽  
Mg Alloy ◽  
Corrosion Properties ◽  
Metal Matrix Nanocomposites ◽  
Friction Stir ◽  
Average Grain Size

Magnesium (Mg) and its alloys have attached more and more attention because of their potential as a new type of biodegradable metal materials. In this work, AZ31/ZrO2 nanocomposites with good uniformity were prepared successfully by friction stir processing (FSP). The scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to characterize the microstructure of the composites. The mechanical properties, electrochemical corrosion properties and biological properties were evaluated. In addition, the effect of reinforced particles (ZrO2) on the microstructure and properties of the composite was studied comparing with FSP AZ31 Mg alloy. The results show that compared with the base metal (BM), the AZ31/ZrO2 composite material achieves homogenization, densification, and grain refinement after FSP. The combination of dynamic recrystallization and ZrO2 particles leads to grain refinement of Mg alloy, and the average grain size of AZ31/ZrO2 composites is 3.2 μm. After FSP, the c-axis of grain is deflected under the compression stress of shoulder and the shear stress of pin. The ultimate tensile strength (UTS) and yield strength (YS) of BM were 283 and 137 MPa, respectively, the UTS and YS of AZ31/ZrO2 composites were 427 and 217 MPa, respectively. The grain refinement and Orowan strengthening are the major strengthening mechanisms. Moreover, the corrosion resistance in simulated body fluid of Mg alloy is improved by grain refinement and the barrier effect of ZrO2.

Influence of Process Parameters on Microstructure of Friction Stir Processed Mg AZ31 Alloy

2014 ◽  
Vol 2 (1) ◽  
pp. 47-58
Author(s):  
G. Venkateswarlu ◽  
M.J. Davidson ◽  
G.R.N. Tagore ◽  
P. Sammaiah
Keyword(s):  
Plastic Deformation ◽  
Grain Refinement ◽  
Process Parameters ◽  
Tilt Angle ◽  
Friction Stir Processing ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Homogeneous Microstructure ◽  
Influence Of Process Parameters ◽  
Friction Stir

Friction stir processing (FSP) has been developed on the principles of friction stir welding (FSW) as an effective and efficien new method for grain refinement and microstructural modification, providing intense plastic deformation as well as higher strain rates than other conventional severe plastic deformation methods. FSP produces an equiaxed homogeneous microstructure consisting of fine grains, resulting in the enhancement of the properties of the material at room temperature. The objective of the present paper is to examine the influence of friction stir processing (FSP) parameters namely tool rotational speed (RS), tool traverse speed (TS) and tool tilt angle (TA) on the microstructures of friction stir processed AZ31B-O magnesium alloy. This investigation has focused on the microstructural changes occurred in the dynamically recrystallised nugget zone/ stir zone and the thermo mechanically affected zone during FSP. The results presented in this work indicate that all the three FSP process parameters have a significant effect on the resulting microstructure and also found that the rotational speed has greatly influenced the homogenization of the material. The grain refinement is higher at intermediate rotational speed (1150 rpm), traverse speed (32 mm / min and tilt angle (10). It is established that FSP can be a good grain refinement method for improving the properties of the material.

Development and Parametric Optimisation of Pure Magnesium Matrix Surface Composite by Friction Stir Processing

2021 ◽  
Vol 9 (2) ◽  
pp. 79-95
Author(s):  
Balraj Singh ◽  
Jagdev Singh ◽  
Ravinder Singh Joshi
Keyword(s):  
Process Parameters ◽  
Friction Stir Processing ◽  
Mechanical Performance ◽  
Plunge Depth ◽  
Friction Stir ◽  
Surface Composite ◽  
Cooling Temperature ◽  
Matrix Surface ◽  
Taguchi’S Technique ◽  
Tool Cooling

Friction stir processing (FSP) is an emerging method for improving surface properties of materials by composite fabrication. This study aims at optimizing the major FSP parameters and analysis of their real-time influence on the mechanical performance of a surface composite fabricated with Magnesium (Mg) matrix and Titanium Carbide (TiC) as reinforcement. Effects of different process parameters, tool rotational speed, plunge depth, the linear speed of the tool, cooling condition, and number of FSP passes have been examined. Using L27 array, a total of 27 combinations of these process parameters were analyzed by taking microhardness as an output response to find influential parameters by Taguchi's technique. Maximum micro-hardness was achieved when tool rpm of 600, cooling temperature of -10o C, tool feed of 15 mm/min, plunge depth of 0.35 mm, and 3 passes of FSP tool were chosen with the help of Taguchi's method. Analysis of variance indicated that cooling temperature, the tool feed, and the number of passes of the FSP tool were the most significant parameters.

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