The document discusses strategies to enhance friction stir welding of aluminum alloys. It describes how tool rotation direction, welding medium, and reinforcement with nanomaterials can improve joint quality and properties. Specifically, it notes that counterclockwise tool rotation and submerged welding in water reduce weld defects compared to clockwise rotation and air welding. It also explains how reinforcing with silicon carbide nanoparticles increases strength, hardness, and wear resistance by restricting grain growth and reducing size through the pinning effect.

1. SUBMITTED BY
JAYESH GUPTA
2020PGMFMS10
PRODUCT DESIGN AND
DEVELOPEMENT
STRATEGIES TO ENHANCE THE
FRICTION STIR WELDING OF
ALUMINIUM AND ITS ALLOYS
SEMINAR 1
1

2. INTRODUCTION TO FSW
• FRICTION STIR WELDING IS A SOLID STATE WELDING PROCESS
• IN FSW, A NON-CONSUMABLE ROTATING TOOL GENERATES FRICTIONAL
HEAT BETWEEN THE TOOL AND THE WORK PIECE MATERIAL,
WHICH INDUCES SEVERE PLASTIC DEFORMATION OF THE METAL INTERFACE,
RESULTS IN MIXING OF THE WORK PIECE MATERIALS ALONG THE
WELDING PATH.
• FIG: FRICTION STIR WELDING [1]
• FSW IS NATURE FRIENDLY PROCESSAS IT DOES NOT EMIT HARMFUL GASES
• FSW HAS LESS ENERGY CONSUMPTION AS COMPARED
2

3. DIFFERENT ZONES:
 Joint of FSW is divided into three distinct zones:
 (a) the stirred zone (SZ) or nugget zone at which severe plastic deformation takes place
 (b) thermo mechanically affected zone (TMAZ), which is found between heat-affected zone and stirred
zone
 (c) heat-affected zone (HAZ), which experienced thermal cycle because of welding process [3]
 Heat due to friction and plastic deformation in SZ leads to fine recrystallized microstructure, while TMAZ
shows the elongated grains [3]
3

4. WHY ALUMINIUM?
 High-strength aluminum alloys are commonly used in modern industry because they are lightweight
 highly durable
 high specific strength,
 high plasticity,
 good corrosion resistance
 excellent machinability.
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5. TOOL GEOMETRY:
 OPTIMUM TOOL DESIGN WILL PRODUCE THE DESIRED JOINT QUALITY WITH HIGHER TOOL LIFE AND
ENABLES HIGH WELDING SPEED
 THERE ARE VARIOUS SHAPES OF TOOL
 FLAT
 GROVED ETC.
 THE TOOL NIB HAS LENGTH SLIGHTLY LESS THAN THICKNESS OF WORL PIECE
 THE TOOL NIB HAS DIAMETER ABOUT ONE THIRD OF TOOL SHOULDER.
 THE SHAPE OF SHOULDER AFFECTS MATERIAL FLOW AROUND THE TOOL NIB
5

6. DIFFERENT STRATEGIES USED IN FSW:
 IN THIS TOPIC WE WILL MAINLY SEE THE DIFFERENT DIFFERENT
STRATEGIES USED TO IMPROVE OR ENHANCE THE FSW , ENHANCE THE
PROPERTIES OF BASE METAL ETC
6

7. 1. Improvement of Formation Quality for
Friction Stir Welded Joints by changing
parameters like tool rotation direction and
changing the medium of FSW .
 The formation quality of friction stir welded joints relies on the deformation ability and flow of
the metal around the FSW tool. Inappropriate weld parameters and conditions result in weld
defects, such as flashes, tunnels, and voids.
7

8.  submerged FSW improves the mechanical properties of friction stir welded joints [6]
 The principle of submerged FSW is that the welds are placed into a liquid medium, and weld
processing is carried out under a specific ambient temperature. This method is highly suitable for
aluminum alloys that are sensitive to excessive heating during welding processes [6]
 joint welded using a stir tool rotated in a counterclockwise direction exhibits better formation
quality than does the joint welded in a clockwise direction. [6]
 Now we will consider a case in which we will discuss how tool rotation and welding medium affect
FSW at different - different tool travel speed and tool rotation speed. [6]
8

9. In the Fig 1 we can see the TUNNEL DEFECT in advancing side .
The size of the tunnel defect decreases with increasing travel speed, but not with rotational speed.
This result indicates that decreasing weld heat input under the same weld conditions prevents tunnel
defects at the AS of the friction stir welded joints
In fig 2 Although the weld defects continue to form under all weld parameter ranges, the size of the
weld defects clearly decreases
Fig 1 Cross-section morphology of the joints fig2 cross section morphology of the joint
welded in water with different welding parameters welded in air with different parameters
and clockwise rotational direction of the FSW tool [6] and clockwise rotation direction of the [6]
9

10. 2. NANOMATERIALS REINFORCEMENT IN
FRICTION STIR WELDING
 Nanomaterial reinforced friction stir welding (FSW) is an emerging domain, as it delivers a
promising method for enhancing joint properties by making composite joints. Composite
joints can enhance surface properties like hardness, strength, corrosion resistance, wear
resistance, fatigue life, electrical conductance.[2]
 Mishra et al. initiated an innovative application of FSW known as friction stir processing (FSP)
method to enhance microstructure and mechanical features of the workpiece.
 Their work comprises using of FSP method to produce metalmatrix composite (MMC).
 They placed reinforcement particles at the upper surface of AA5083 alloy and after that FSP
method applied at that surface. [1]
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11.  He observed an enormous improvement of mechanical strength and microhardness
(almost double as compared to the base metal)
 So for the study we use silica carbide as nano material
The size of the reinforcement particle is very crucial in deciding the properties of joint
 particles size affects the joint properties most significantly as by increasing particle size tensile strength
and the hardness decreases.
 The best result came with the lowest particle size reinforcement. [2]
 According to Zener pinning effect, in the presence of reinforcement particles, the grain boundary
movement, which is migrating because of the growth of grain and recrystallisation, may be pinned by
reinforcement particles. [4]
 In the FSW of AA7075-O aluminium alloy, with and without SiC nanoparticles reinforcement
Grain Size with powder 3.6 mm and without powder 4.83 mm was observed due to acting of SiC
nanoparticles as grain boundary movement suppressor [2]
11

12.  So basically reinforcing particles serve as barriers against grain boundaries and hinder its growth
by limiting their movement known as pinning effect.
FIG: Grain growth pinning by reinforcement particles[2]
 The grain size of the aluminium nugget zone has been decreased from 49.8 mm (AA2024) and
56.5 mm (AA6061) to 7.4 mm because of SiC nanoparticles. [2]
12

13. 13

14. FIG: FE-SEM images for the six passes processed dissimilar joint at different magnifications. The red arrow is
IMC streaks, the Green circle is SiC nanoparticles, and the blue circle is the fragment of
steel [2]
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15.  Dispersal of the nanomaterial reinforcements in a homogenous fashion into the metal matrix is a major
challenge. Due to the high surface area, there is always a tendency of nanoparticles to agglomerate
 Agglomeration increases interparticle spacing and produces pores which result in a decrease in the strength of
nanocomposites
 To minimise the size of the cluster or agglomeration for uniform distribution of reinforcing nanoparticles
inside the nugget zone effect of the number of tool pass has been investigated.
 It is reported that there is a significant amount of reduction in cluster size using two passes as compare to that
single tool pass. [2]
 As shown in fig. The first FSW pass improves the grain
refinement and formation of agglomerated nanoparticles in
the SZ of joint. As the further increase in FSW passes, more
agglomerated SiC nanoparticles separated; and hence their
homogenous distribution occurs. Henceforth, the coherency
between SiC nanoparticles and matrix increased [2]
 Fig. FE-SEM images of reinforced (a) one pass,
(b) four passes and (c) six passes of FSW
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16. Effect of nanomaterials reinforcement on
FSW joint properties in aluminium alloys
1. On mechanical properties:
increased tensile strength
increased micro hardness
h
FIG: plot of microhardness curve[5] FIG: plot of UTS curve[5]
16

17.  2. Electrochemical properties
It is been observed that by using this method wear rate is reduced
decrease of wear rate for joint with SiC is very significant as it comes 0.37 g/m, as .
compared to wear rate of unreinforced joint 0.96 g/m. [2]
CONCLUSION:
 BY THIS DIFFERENT PROPERTIES ARE IMPROVED LIKE TENSILE STRENGTH , HARDNESS , LESS WEAR RATE ETC.
 Nanomaterials have efficiently suppressed inevitable welding defects.
 Purging of clustering of reinforcement nanoparticles can be achieved by varying in process parameters and by
using an external source of energy. The goal of nanomaterials as reinforcement is to facilitate in the reduction of
joint’s grain size. The grain size reduction is considered as one of the significant mechanical properties deciding
parameter. [2]
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18. FUTURE SCOPE
 Very few researches have been conducted in the field of nanomaterial
reinforcement FSW. Suitable process parameter still needs to be
investigated
 Since ceramic nanoparticle is very hard in nature, thus wear of welding tool
still need to be investigated.
 Method of deposition of nanoparticles during FSW must be improved.
 Till now nanoparticle reinforcement applied mostly on aluminium alloys.
So, it must be addressed for other material too.
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19.  REFRENCES:
 [1]Yi D, Onuma T, Mironov S, Sato YS, Kokawa H. Evaluation of heat input during friction stir welding of aluminium alloys. Sci Technol Weld
2016; 22:41e6. https://doi.org/10.1080/ C13621718.2016.1183079
 [2]Sufian Raja a, Mohd Ridha Muhamad a,b,*, Mohd Fadzil Jamaludin b, Farazila Yusof a,b, j o u r n a l of ma t e r i a l s r e s e arch and
technology 2 0 2 0 ; 9 ( 6 ) : 1 6 4 5 9 e1 6 4 8 7
 [3] Zolghadr P, Akbari M, Asadi P. Formation of thermomechanically affected zone in friction stir welding. Mater Res Express 2019;6.
https://doi.org/10.1088/2053-1591/ ab1d25. 0e11.
 [4]Rohrer GS. Introduction to grains, phases, and interfaces-an interpretation of microstructure. Trans AIME 1948;175:15e51.
https://doi.org/10.1007/s11661-010-0215-5. by C.S. Smith. vol. 41. 2010.
 [5]Dragatogiannis DA, Koumoulos EP, Kartsonakis IA, Pantelis DI, Karakizis PN, Charitidis CA. Dissimilar friction stir welding between 5083 and
6082 Al alloys reinforced with TiC nanoparticles. Mater Manuf Process 2016;31:2101e14. https://doi.org/10.1080/10426914.2015.1103856.
 [6] R.-D. FU, R.-C. SUN, F.-C. ZHANG, AND H.-J. LIU . Improvement of Formation Quality for Friction Stir Welded Joints
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