Optimization of Process Parameter of FSP Cladded AZ31B
Magnesium Alloys
K. Ganesa Balamurugan & K. Mahadevan
Dept. of Mechanical Engineering, Pondicherry Engineering College,
Pondicherry -605014, India.
E-mail : [email protected], [email protected]
used in this study. The specimen size of AZ31B alloy
was 40x100x6 mm and the specimen size of Al5086
alloys was 38x100x2 mm. A groove of size 38x100x1.5
mm was taken in the AZ31B alloy and the Al5086 alloy
clad plate was placed in it for proper contact between
the two plates. CNC vertical milling center was used to
perform the FSP on the plates. A concave shoulder tool
of 18mm shoulder diameter and 5mm pin diameter with
strait flutes was used. The tool material was HCHCr
hardened to 58 HRC. The processing Al5086 alloy
placed on AZ31B magnesium plates were clamped on
the machine table using a fixture. After activation of
preset program in the CNC machining center, the tool
performed the FSP on the specimens to clad Al5086
aluminium alloy with AZ31B magnesium plate. A
constant tool depth of 4.2mm was maintained
throughout the process. The tool rotational speed and
tool travel speed values used are given in the Table.1
and Table.2 shows the mixed Taguchi’s L8 orthogonal
array experiment design. The FSP operation was carried
out on AZ31B magnesium alloy without cladding of
Al5086 alloy with same process parameter values for
comparison. The processed specimens were subjected to
mechanical tests and tribological tests as per ASTM
standards. Tensile tests were conducted as per ASTM
B557; Micro hardness test was performed as per ASTM
E384. Corrosion tests were conducted as per ASTM
G59-97e1 and Wear tests were conducted as per ASTM
G99.
Abstract – Al5086 aluminium alloy was successfully
cladded on the AZ31B magnesium alloy using friction stir
processing. The experiments were conducted as per
Taguchi mixed design model. The mechanical and
tribological tests were conducted as per ASTM standards.
Taguchi method optimization was used to optimize the
responses and ANOVA technique was used to identify the
significant factor for each responses.
Index Terms— Aluminium cladding, AZ31B magnesium
alloy, ANOVA, FSP, Taguchi method.
I.
INTRODUCTION
Light weight metallic alloys are the primary
concern of the present day automotive, aerospace and
electronic industries [1-3]. The magnesium alloys satisfy
the above desire of the industries by its low density and
high specific strength [4-6]. However, the formability
and the tribological properties of magnesium alloys are
not commendable [7-8]. To overcome these limitations
many researchers attempted to modify the surface of the
bare magnesium alloys with several coating techniques
like electrochemical plating, conversion coating, plasma
coating and anodizing [9]. Recently some researchers
have identified friction stir processing (FSP) as a unique
surface modification technique [10-11]. In the present
work an attempt was made to clad Al5086 aluminium
alloy on AZ31B magnesium alloy using friction stir
processing. Taguchi method of optimization was used to
find the optimum parameter set for each response and
ANOVA technique was used to identify the significant
factor for each response.
Table.I Process parameters and their values
II. EXPERIMENTAL PROCEDURE
Commercially available AZ31B magnesium alloy
and marine grade Al 5086 aluminium alloy plates were
Tool Rotational Speed in
[RPM]
Tool Travel Speed
in [mm/min]
500
14
710
850
1000
20
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46
International Journal on Mechanical Engineering and Robotics (IJMER)
Table.II Experimental Design
Exp.
No.
Tool Rotational
Speed [RPM]
Tool Travel Speed
[mm/min]
01
500
14
02
500
20
03
710
14
04
710
20
05
850
14
06
850
20
07
1000
14
08
1000
20
III. RESULTA AND DISCUSSION
Table.III shows the results of the Al5086 cladded
AZ31B magnesium alloys.
Table.III Experimental Results
Tensile
Strength
(MPa)
Microhardness
(Hv)
Corrosion
Rate
Wear
Losses
(mm/yr)
(mg)
01
205
80.4
8.27E-07
1.10
02
236
120
1.86E-06
0.70
03
185
82.2
1.10E-06
0.95
04
215
80.7
9.70E-06
1.08
05
181
86.8
1.52E-06
0.87
06
142
83.4
1.75E-06
0.90
07
166
80.5
0.000286
0.94
08
174
91.6
0.003522
0.83
Exp.
No.
A. Optimization
Taguchi method of optimization is used to optimize
the process parameters sets.
For Corrosion rate and Wear Losses Smaller the
Better strategy is used
For Tensile strength and Microhardness Larger the
Better strategy is used
Fig.1 Shows the S/N ratios of the responses
Formula for smaller the better strategy is S/N= -10
x log ((1/n)ΣYi);
The following Table.IV shows the optimized
parameter set for each response
Formula for larger the better strategy is S/N= -10 x
log (1/(n*ΣYi));
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International Journal on Mechanical Engineering and Robotics (IJMER)
Table. IV Optimized parameter set for each response
Response
Tensile
strength
Larger
Better
the
Microhardness
Larger
Better
the
Smaller
Better
the
Smaller
Better
the
Rate
Wear losses
Source
DF
SS
MS
F
F
Critical
Rotational
Speed
3
1.166E-05
3.88E06
802.559
4.07
Travel
Speed
1
24.50
24.50
5.05E+09
5.32
Interaction
3
-24.50
-8.167
-1.6E+09
3.84
Residual
8
3.87E-08
4.84E09
Total
15
2.30E-05
Optimized
parameter set
Strategy
Corrosion
Table.VII ANOVA for Corrosion rate
500 rpm-20 mm/min
500 rpm-20 mm/min
500 rpm-14 mm/min
500 m-20
mm/min
Table.VIII ANOVA for Wear losses
Source
DF
Rotational
Speed
3
Travel
Speed
1
Interaction
3
SS
MS
F
F
Critical
2.42
8.07E16
1.424
4.07
24.50
24.50
4.3E+16
5.32
24.50
-8.16
1.44E+16
3.84
4.534
5.67E16
B. Identification of significant factor
The significant factor of this experiment was
identified using ANOVA technique. Using Minitab
software, for α=0.05 significance, the ANOVA tables
were generated. Table V, Table VI, Table VII, Table
VIII show the ANOVA results of the Tensile strength,
Microhardness, Corrosion rate and Wear losses
respectively.
Residual
8
Table.V ANOVA for Tensile Strength
Total
Source
DF
SS
MS
F
F
Critical
Rotational
Speed
3
8894.3
2964.75
1824.75
4.07
Travel
Speed
1
210.3
210.25
129.38
5.32
Interaction
3
3228.3
1076.08
662.21
3.84
Residual
8
13.0
1.63
Total
15
12345.8
15
7.24
Table IX shows the summarized results of ANOVA.
Table IX Significant factors for the responses
Table.VI ANOVA for Microhardness
Responses
Significant Factor
Tensile Strength
Rotational Speed
Microhardness
Travel Speed
Corrosion Rate
Travel Speed
Wear losses
Travel Speed
IV. CONCLUSION
Source
DF
SS
MS
F
F
Critical
Rotational
Speed
3
1040.90
346.96
1.35E+15
4.07
Travel
Speed
1
627.50
627.50
2.45E+15
5.32
Interaction
3
1728.48
576.16
2.25E+15
3.84
Residual
8
0.00
0.00
Total
15
3396.89
In this work an attempt was made to clad Al5086
aluminium alloy on AZ31B magnesium alloy using
friction stir processing. Taguchi method of optimization
was used to find the optimum parameter set for each
response and ANOVA technique was used to identify
the significant factor for each response. The following
results were obtained;
1.
For responses like Tensile strength, Microhardness
and Wear losses 500 rpm-20 mm/min parameter set
was identified as optimum set.
2.
For Corrosion rate 500 rpm-14 mm/min parameter
set was identified as optimum set.
ISSN (Print): 2321-5747, Volume-1, Issue-2, 2013
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International Journal on Mechanical Engineering and Robotics (IJMER)
3.
For Tensile strength, rotational speed was identified
as significant factor.
4.
For Microhardness, Corrosion Rate and Wear
losses, travel speed was identified as significant
factor
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