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1. PROJECT REVIEW
MICRO AND STRUCTURAL
TESTING OF FRICTION STIR
WELDED ALUMINIUM 7075
& 5052 SQUARE PLATE
Presented By
JINU JANE RUSSEL J
REG. NO : 960321410009
M.E – MANF. ENGINEERING
DEPARTMENT OF MECHANICAL ENGINEERING
BETHLAHEM INSTITUTE OF ENGINEERING
Guided By
Mr. A. AJISH, M.E.,
ASSISTANT PROFESSOR
DEPARTMENT OF MECHANICAL ENGINEERING
BETHLAHEM INSTITUTE OF ENGINEERING

2. ABSTRACT
 Friction Stir Welding (FSW) is a solid-state process that can be beneficially used
for various transportation and defense applications.
 Understanding the microstructure evolution and properties of friction stir welded
components is necessary to use this new process in critical structural applications.
 The behaviour of friction stir welded Al7075 with Al5052 wrought aluminium
alloys were investigated in the direction parallel to the friction stir welding
direction.
 The effects of critical FSW process parameters were also studied. The resulting
microstructural changes, micro hardness, and residual stresses were characterized.

3.  Important process parameters that control the quality of the weld are
a) rotation speed (700rpm) b), traverse speed
(30mm/min&50mm/min).
 The main aim of this project is to find the mechanical properties of
friction stir welding of dissimilar aluminum alloys (7075&5052) by
using friction stir welding machine.
 Three experiments being used are the Tensile Testing, Hardness
testing and Optical Microscopy (OM) to get the strength of the joint
and the metallographic studies.
 Friction Stir Welding (FSW) is a solid-state process that can be
beneficially used for various transportation and defence applications.

4. INTRODUCTION
 Friction stir welding (FSW) is a solid-state joining process that uses a
non-consumable tool to join two facing workpieces without melting the
workpiece material.
 Heat is generated by friction between the rotating tool and the
workpiece material, which leads to a softened region near the FSW tool.
 While the tool is traversed along the joint line, it mechanically
intermixes the two pieces of metal, and forges the hot and softened
metal by the mechanical pressure, which is applied by the tool, much
like joining clay, or dough.
 It is primarily used on wrought or extruded aluminium and particularly

5. Friction Stir Welding
 Friction Stir Welding (FSW) is considered to be the most
significant development in metal joining in a decade and is a
“green” technology due to its energy efficiency, environment
friendliness and versatility.
 As compared to the conventional welding methods, FSW
consumes considerably less energy. No cover gas or flux is
used, thereby making the process environmentally friendly.
 The joining, does not involve any use of filler metal and
therefore any aluminum alloy can be joined without concern
for the compatibility of composition.

6. friction stir welding

7. LITERATURE REVIEW
Ava Azadi Chegeni, “A Microstructural Evaluation of Friction Stir Welded 7075
Aluminum Rolled Plate Heat Treated to the Semi-Solid State” Two rolled plates
of 7075 aluminum alloy were used as starting material. The plates were welded using
a simultaneous double-sided friction stir welding (FSW) process. One way of
obtaining feedstock materials for Semi-solid processing or forming is via deformation
routes followed by partial melting in the semi-solid state. As both the base plate
materials and the friction weld area have undergone extensive deformation specimens
were subjected to a post welding heat-treatment in the semi-solid range at a
temperature of 628 C, for 3 min in order to observe the induced microstructural
changes.

8. Navaneethakrishnan. T, “Effect Of Welding Parameters On
Friction Stir Welded Dissimilar Aluminum Alloys 7075 And
6082 With Various Tool Pin Profiles” The aim of the present
study is to investigate the effect of different tool pin profiles over
Friction Stir Welding of dissimilar AA 6082 –T6 and AA 7075 –
T6. The parameters considered were tool rotation speed, welding
speed, tool pin profiles and number of passes. The metallurgical
and mechanical characterization of friction stir welds of
aluminium alloy 6082 – T6 with 7075 – T6 were carried out.
Multi pass Friction Stir Welding of the alloys was also performed.
This work includes microstructure examination, micro hardness
test and tensile tests.

9. MATERIAL DESCRIPTION
ALUMINIUM AL7075
Aluminum alloys have strong corrosion resistance. At subzero
temperatures, their strength increases, thus making them a
useful low-temperature alloy. Their strength decreases if they
are subjected to very high temperatures. The aluminum 7075
alloy has high strength. 7075 aluminium alloy is an aluminium
alloy, with zinc as the primary alloying element.
Element Content (%)
Aluminum, Al 90
Zinc, Zn 5.6
Magnesium, Mg 2.5
Copper, Cu 1.6
Chromium, Cr 0.23

10. ALUMINIUM AL5052
The alloy composition of 5052 is
1. Magnesium - 2.2%-2.8% by weight
2. Chromium - 0.15%-0.35% maximum
3. Copper - 0.1% maximum
4. Iron - 0.4% maximum
5. Manganese - 0.1% maximum
6. Silicon - 0.25% maximum
7. Zinc - 0.1% maximum
8. Others each 0.05% maximum
9. Others total 0.15% maximum
10. Remainder Aluminium

11. EXPERIMENTAL SETUP
FRICTION STIR WELDING MACHINE
A unique and innovative method of jointing metals, friction stir welding
uses frictional heat combined with precisely controlled forging pressure to
produce high integrity, full penetration welded joints that are virtually defect
free. Due to a very low welding temperature, mechanical distortion is
practically eliminated, with minimal Heat Affected Zone (HAZ), and an
excellent surface finish. The FSW process is effective on flat plated,
cylindrical components and even parts of irregular thickness. Powerstir
Friction Stir Welding machines have attracted considerable interest from
organisations seeking an innovative way of creating superior, high strength
welded joints, without the detrimental and visible effects typically associated
with conventional welding. Developed for a broad range of applications - with
special attention paid to structural rigidity and the load-sensing requirements
of the FSW process.

13. METHODOLOGY

14. EXPERIMENTAL RESULTS
HARDNESS TEST
Location
Welding Speed (mm/min)
30 50
Sample-1 Sample-2
1 107.1 114.7
2 102.1 118.2
3 109.6 115.8

15.  The Brinell micro hardness was measured at cross section perpendicular to the
welding line in order to investigate the variation of hardness at different
welding region fig. shows the effect of tool rotational speed on the hardness of
the stir zone.
 All friction stir welded joints produced a softened region comprised of weld
nugget zone (WNZ) and heat affected zone (HAZ) which is directly supporting
the findings of the tensile properties of the welded joints as mentioned in the
previous sections.
 The average microhardness found at the weld nugget zone was lower (48.8–
54.2 Hv) compared to base material (58.3 Hv). The average microhardness
of the weld nugget zone was increased from 52.9 to 54.2 Hv when the tool
rotational speed increased from 800 rpm to 1000 rpm.
 The average microhardness corresponds to 1500 rpm, 2000 rpm and 3000 rpm
were 51.6 Hv, 49.6 Hove and 48.8 Hv respectively. It is well documented that,
at a constant traverse speed, as the tool rotational speed increased the rate of
heat input also increased.

16.  High heat input resulted in the dissolution of second phase particles with a
great extent. However, it is believed that the improved weld nugget hardness
from 800 rpm to 1000 rpm was due to a reduction in the density of coarse
second phase particles and a greater post weld natural aging response .
 The microhardness at retreating side was always greater than the advancing
side that caused the microhardness curve asymmetrical across the welding
center line.
 During the friction stir welding advancing side experienced more plastic strain
than the retreating side which was in turn resulted in higher heat generation
close to weld center line.
 This non-uniform heat caused non-uniform plastic flow in two sides. Thus it
is believed that, the non-uniform plastic flow had a considerable effect on
the variation of the microhardness at two welding side. A similar study was
also reported by Aval et al. in case of friction stir welding of AA 7075 alloy

17. TENSILE TEST
Specimen 1 (Without FSW)

18. Specimen 2 (With FSW)

19. MICRO STRUCTURE ANALYSIS

20.  According to the weld surface, macrostructure and tensile strength
of the joints welded at different conditions, the optimum condition
can be achieved at rotational speed of 700 rpm, traverse speed of 40
mm/min, pin offset of 5.7 mm and clockwise rotation condition.
 For this reason the microstructure and hardness of the joint welded
at the optimum condition have been studied. The OM analysis were
used for investigating the formation of inter metallic compound in
interface of aluminum alloys.
 However, the OM line scan of the interface between steel particle
fragments and Al suggests that intermetallic compound has been
formed in this region. According to the Fe-Al binary phase diagram
and OM result, it can be concluded that the FeAl3 inter metallic
compound form in the interface of the Al7075 fragment and Al5052
alloy.

21. CONCLUSION
Dissimilar friction stir welds between Al7075 & Al5052 were obtained
with different tool rotation speed, tool traverse speed and tool design. The
defect free joints were obtained. The results can be concluded as follows The
welding speed influences the formation of plastic flow region. The joints
fabricated at the lowest or highest welding speeds show the absence of mixed
flow region. The joints produced at a welding speed of 40mm/min show
better tensile properties. The dissimilar joint shows the presence of various
zones such as weld affected zone (TMAZ) and heat affected zone (HAZ). The
joints produced at a welding speed of 40mm/min show better then the welding
speed of 20mm/min . The results showed that if annealing occurred at the weld
zone ,the strength of the joints would reduce.

22. REFERENCES
1[1] Jameson E.C. (2001), Electrical Discharge Machining, first ed.,
Society of Manufacturing Engineers, Michigan.
[2] Ho K.H., Newman S.T. (2003), State of the art electrical discharge
machining (EDM), International Journal of Machine Tools and
Manufacture, 43(5): 1287–1300.
[3] Abbas N.M., Solomon D.G., Bahari M. Fuad(2007), A review on
current research trends in electrical discharge machining, International
Journal of Machine Tools and Manufacture, 47(3): 1214–1228.
[4] Kumar S., Singh R, Singh T.P., Sethi B.L. (2009), Surface
modification by electrical discharge machining: a review, Journal of
Materials Processing Technology, 209(6): 3675–3687.

23. THANK YOU