Simulation of Material Flow and Heat Evolution in Friction Stir Processing Incorporating Melting

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
H. W. Nassar ◽  
M. K. Khraisheh
Keyword(s):  
Friction Stir Processing ◽  
Rotational Speed ◽  
Material Flow ◽  
Heat Evolution ◽  
Heat Of Fusion ◽  
Maximum Temperature ◽  
Molten Layer ◽  
Local Melting ◽  
Friction Stir ◽  
Microstructure Refinement

Friction stir processing (FSP) is a relatively new technology for microstructure refinement of metallic alloys. At high processing speeds, excessive heating due to severe plastic deformation and friction may result in local melting at the interface between the FSP tool and the workpiece. In this work, a computational fluid dynamics (CFD) approach is applied to model material flow and heat evolution during friction stir processing of AZ31B magnesium alloy, taking into consideration the possibility of local melting in the stirring region. This is achieved by introducing the latent heat of fusion into an expression for heat capacity and accounting for possible effects of liquid formation on viscosity and friction. Results show that the temperature in the stirring region increases with the increase in rotational speed and drops slightly with the increase in translational speed. As liquid phase begins to form, the slope of temperature rise with rotational speed decreases and the maximum temperature in the stirring region stabilizes below the liquidus temperature at high rotational speeds. It is also shown that the formation of a semi-molten layer around the tool may result in a reduction in the shearing required for microstructure refinement.

Material flow modeling for the DSFSW of magnesium alloy

2020 ◽  
pp. 030932472097661
Author(s):  
Parviz Asadi ◽  
MohammadHosein Mirzaei
Keyword(s):  
Magnesium Alloy ◽  
Rotational Speed ◽  
Material Flow ◽  
Sheet Thickness ◽  
Maximum Temperature ◽  
Flow Modeling ◽  
Az91 Magnesium Alloy ◽  
Friction Stir ◽  
Az91 Magnesium ◽  
Tool Pin

The Coupled Eulerian Lagrangian (CEL) method is utilized to model the double shoulder friction stir welding (DSFSW) of AZ91 magnesium alloy and then the model is verified by the experiments. The effects of tool rotational speed and sheet thickness on temperature and strain distributions as well as the material flow patterns are considered at different steps of the process. The material flow pattern around the tool pin is demonstrated properly and the shoulder driven and pin driven zones are predicted very well. Results show that, the material movement in shoulder driven and pin driven zones is different, while it is from the advancing side (AS) to the retreating side (RS) in the pin driven zone, it is inverse in the shoulder driven zone. Additionally, increase in rotational speed raises the maximum temperature and strain, improves the material movement, expands the SZ width and increases the depth of shoulder driven zone. Furthermore, increase in sheet thickness results in a decrease in maximum temperature and strain as well as the material movement. In the sheets with low thickness due to the effects of two shoulders, the pin driven zone is not distinguishable, however in thicker welding sheets the pin driven zone is obvious by significantly lower strains.

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.

Friction Stir Processing: An Operational Method to Improve Ductility in Pure Copper

2013 ◽  
Vol 818 ◽  
pp. 14-19 ◽  
Author(s):  
Vahid Rezazadeh ◽  
Ali Sharbatzadeh ◽  
Ali Hosseinzadeh ◽  
Amir Safari ◽  
Salar Salahi
Keyword(s):  
Friction Stir Processing ◽  
Rotational Speed ◽  
Pure Copper ◽  
Traverse Speed ◽  
Ultrafine Grain ◽  
Work Piece ◽  
Cavity Formation ◽  
Nugget Zone ◽  
Friction Stir ◽  
Lower Heat

mproving ductility in metals using friction stir processing (FSP) is a challenging effort and is made by means of a rotating tool inserted in a work piece providing heat transfer and plastic deformation. In this investigation, improving ductility during FSP was determined as a purpose and the microstructure and mechanical properties of nugget zone were investigated during friction stir processing (FSP) of pure copper. Ductility was measured using tensile elongations at a temperature of 20 °C. By varying the traverse speed from 40 to 100 mm/min at rotation speeds of 300 and 600 rpm, the ultrafine grain microstructure was achieved .Defects were observed in rotational speed of 300 rpm. By increasing traverse speed at constant rotational speed of 600 rpm grain size of the nugget zone decreased and ductility increased. Achievable ductility was limited by cavity formation due to lower heat input and deformation in samples with defects.

Crack Repair Using Hybrid Additive Manufacturing and Friction Stir Processing

2019 ◽  
Author(s):  
Fadi Al-Badour ◽  
Ibrahim H. Zainelabdeen ◽  
Rami K. Suleiman ◽  
Akeem Adesina
Keyword(s):  
Additive Manufacturing ◽  
Friction Stir Processing ◽  
Welding Speed ◽  
Rotational Speed ◽  
Hardness Test ◽  
Mechanical Tests ◽  
Friction Stir ◽  
Al 6061 ◽  
The Impact

Abstract A hybrid additive manufacturing (AM) and friction stir processing (FSP) was used to heal a crack in 6 mm thick Al 6061-T6 aluminum alloy. AL-6061 is usually used in H2 high-pressure vessel fabrication as well as aerospace applications. In this work, Al-Si powder was utilized to fill the crack, then FSP was applied to consolidate and stir the powder with the base metal to fill and close the crack zone. Effect of FSP parameters including welding speed and tool rotation speed on the quality of repair was studied. Various mechanical tests, as well as characterization techniques such as hardness test, optical microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS), were employed to study the newly developed hybrid process on the quality of the repair. The investigation revealed that low rotational speed of 800 rpm results in minimum variation in microhardness. Moreover, the impact of welding speed on microhardness is smaller as compared to rotational speed.

Role of tool rotational speed on the tribological characteristics of magnesium based AZ61A/TiC composite developed via friction stir processing route

2020 ◽  
Vol 2 (101) ◽  
pp. 60-75
Author(s):  
P. Sagar ◽  
A. Handa
Keyword(s):  
Friction Stir Processing ◽  
Rotational Speed ◽  
Research Work ◽  
Wear Behaviour ◽  
Processing Route ◽  
Tool Rotational Speed ◽  
Tribological Behaviour ◽  
Friction Stir ◽  
Mechanism Research

Purpose: A new composite material was prepared and Different properties such as hardness and tribological behaviour of the fabricated metal matrix composite (MMC) was investigated and compared with the base AZ61A magnesium alloy. Design/methodology/approach: For the current research work, state-of-the-art technology, Friction stir processing (FSP) was performed to develop magnesium based AZ61A/TiC composite at optimized set of machine parameters. Findings: Increasing tool rotational speed ultimately leads in enhanced hardness, which further gives superior tribological properties as compared to base AZ61A alloy. Wear observations suggests a combination of abrasive and adhesive wear mechanism. Research limitations/implications: More microstructural and mechanical properties can be examined. Practical implications: The idea behind selecting AZ61A is mainly due to its increasing use in bicycle pedals and military equipment’s where at certain places it needs to encounter friction. In this current work, microhardness study and wear behaviour of AZ61A/TiC composite processed via FSP were examined. Originality/value: Paper is completely new and no work has been done till date considering this material and preparing composite with nanoparticles TiC.

Effect of Tool Rotational Speed on Microstructure and Microhardness of AA6082/TiC Surface Composites using Friction Stir Processing

2014 ◽  
Vol 592-594 ◽  
pp. 234-239 ◽  
Author(s):  
A. Thangarasu ◽  
N. Murugan ◽  
I. Dinaharan ◽  
S.J. Vijay
Keyword(s):  
Friction Stir Processing ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Tool Rotational Speed ◽  
Friction Stir ◽  
Surface Composite ◽  
Surface Composites ◽  
Homogenous Distribution ◽  
Tool Pin ◽  
Scanning Electron

Friction stir processing (FSP) is as a novel modifying technique to synthesize surface composites. An attempt has been made to synthesis AA6082/TiC surface composite using FSP and to analyze the effect of tool rotational speed on microstructure and microhardness of the same. The tool rotational speed was varied from 800 rpm to 1600 rpm in steps of 400 rpm. The traverse speed, axial force, groove width and tool pin profile were kept constant. Scanning electron microscopy was employed to study the microstructure of the fabricated surface composites. The results indicated that the tool rotational speed significantly influenced the area of the surface composite and distribution of TiC particles. Higher rotational speed provided homogenous distribution of TiC particles while lower rotational speed caused poor distribution of TiC particles in the surface composite. The effect of the tool rotational speed on microhardness is also reported in this paper.

Experimental Study on Friction Stir Welding of Dissimilar Al 6061 to Trip 780/800 Steel

2014 ◽  
Author(s):  
Xun Liu ◽  
Shuhuai Lan ◽  
Jun Ni
Keyword(s):  
Friction Stir Welding ◽  
Cross Sections ◽  
Welding Speed ◽  
Rotational Speed ◽  
Maximum Temperature ◽  
Friction Stir ◽  
Al 6061 ◽  
Tool Axis ◽  
Edge Temperature ◽  
Welding Force

Friction stir welding (FSW) of dissimilar Al 6061 and TRIP 780/800 steel has been performed under different process parameters, including tool rotational speed, welding speed as well as the relative position of the tool axis to the abutting edge. Temperature and mechanical welding force was recorded during the process. Welding speed has an insignificant effect on either the maximum temperature or welding force. However, it can directly change the length of high temperature duration, which will accordingly influence temperature distribution in the weld and the microstructure. Higher rotational speed can effectively elevate weld temperature through greater amount of heat input. Metallurgical observations on weld cross sections perpendicular to the joint line was performed using both optical and scanning electron microscope. Microstructure evolution was analyzed and related to the force and temperature measurement results during the FSW process.

Friction Stir Processing of Cast NiAl Bronze

2007 ◽  
Vol 539-543 ◽  
pp. 3721-3726 ◽  
Author(s):  
Murray W. Mahoney ◽  
Christian B. Fuller ◽  
William H. Bingel ◽  
Michael Calabrese
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Friction Stir Processing ◽  
Material Flow ◽  
Lessons Learned ◽  
Friction Stir ◽  
Tool Materials ◽  
Surface Areas ◽  
Percent Increase ◽  
Long Life

Friction stir processing (FSP) of cast NiAl bronze has resulted in significant increases in properties including more than doubling the yield greater that 40 percent increase in the threshold fatigue life; all achieved while increasing ductility. These and other strength, greater than a 60 percent increase in tensile strength, and property improvements were realized following studies of FSP procedures specifically for NiAl bronze. Within this manuscript, FSP procedures and other “lessons learned” are presented. Details of property improvements are documented elsewhere within this conference proceedings (see Fuller et al.). Presented herein are tool designs for efficient material flow, tool materials capable of long life at 1000°C, rastering procedures covering large surface areas, and other results pertinent to achieve improved properties in cast NiAl bronze following friction stir processing.

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