Research Journal of Applied Sciences, Engineering and Technology 4(16): 2682-2694, 2012
ISSN: 2040-7467
© Maxwell Scientific Organization, 2012
Submitted: March 15, 2012
Accepted: April 13, 2012
Published: August 15, 2012
Investigation on the Effect of Roller Burnishing Process on the Surface Quality
and Microhardness of Cu-Zn-Al Sma Alloys
S.M.A. Al-Qawabah
Mechanical Engineering Department, Tafila Technical University,
Amman 11942, P.O. Box 13720, Jordan
Abstract: Burnishing is a plastic deformation process that can be used to finish surfaces by plastic deformation
of surface irregularities. The burnishing is chipless machining which can be used to improve the surface
roughness and surface hardness on any metal work piece. The purpose of the research was to demonstrate the
roller burnishing process on Cu-Zn-AL to enhance the mechanical properties of Cu-Zn-Al shape memory alloy
and improve surface quality and surface microhardness. The experiments were carried on Cn-Zn-Al SMA using
CNC turning machine with various spindle rotations, feed rates and depth of penetration, where a roller
burnishing tool was designed and manufactured to be used in this investigation. It was found that the surface
roughness and microhardness on various Cu-Zn-Al SMA were improved by high spindle speed, The best results
were attained at 212 N burnishing force, 50 mm/min feed rate and 1120 rpm.
Keywords: Burnishing process, microhardness, shape memory alloys, surface quality
INTRODUCTION
1200
Stress (MPa)
1000
800
600
400
Austenite
Martensit
200
0
0
5
10
Strain (%)
15
20
Fig. 1: Mechanical behavior of SMA alloy for austenitic and
martensitic structure www.tiniaerospace.com
Heat flow (mJ/s)
Shape Memory Alloys (SMAs) refer to a group of
materials which have the ability to return to a
predetermined shape when heated. The shape memory
effect is caused by a temperature dependent crystal
structure. When an SMA is below its phase
transformation temperature, it possesses low yield
strength as shown in Fig. 1.
While in this state, the material can be deformed into
other shapes with relatively little force. The new shape is
retained provided the material is kept below its
transformation temperature. When heated above this
temperature, the material reverts to its parent structure
known as Austenite causing it to return to its original
shape (Phase Transformation figure). This phenomenon
can be harnessed to provide a unique and powerful
actuator. The most widely used shape memory material is
an alloy of Nickel and Titanium called Nitinol. This
particular alloy has excellent electrical and mechanical
properties, long fatigue life and high corrosion resistance.
Martensite phase can be obtained after the Cu-Zn-Al-MnNi SMA is quenched to ambient temperature and it begins
to transform into parent phase upon heating to above the
initial temperature of reverse martensitic transformation.
This process is reversible during heating and cooling in
the transformation range. The DSC curve upon heating
from martensite phase to parent phase is shown in Fig. 2.
The principle of mechanical surface treatments is
based on the elastic-plastic cold-working in the nearsurface region. After the mechanical surface treatments,
the surface layers are work-hardened and residual
compressive stresses are induced. Hence, the surface
provides a higher resistance to fatigue crack initiation
and/or propagation (Zhang and Lindemann, 2005). In
283
313
343
373
Temperature (K)
403
Fig. 2: DSC curve upon heating from martensite phase to parent
phase (Yu-Jun et al., 2000)
order to properly design a burnishing process, several
controlling parameters have to be considered, namely,
burnishing speed, feed rate, force (or pressure) and ball
size, number of burnishing passes, workpiece material,
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ball material and lubricant (Loh et al., 1989). This process
transforms tensile residual stress induced in the near
surface by machining into compressive residual stresses,
giving several improvements to mechanical properties
(Luo et al., 2005). Stresses in most of the metal forming
processes, such as cold heading, riveting etc., are
compressive in nature. Upset test at room temperature
gives a representative behavior during metal forming
(Avitzur, 1977; Schey et al., 1982; Altan and Bonlger,
1973). Previously published works indicated that
burnished surfaces have many advantages over ground
surfaces (El-Tayeb et al., 2006; Hassan, 1997; Hassan and
Al-Bsharat, 1996; El-Tayeb, 1994; El-Tayeb and
Ghobrial, 1993).
In this investigation the Cu-Zn-Al SMA alloy was
used due to its cheapness and its availability, however the
effect of burnishing process on the surface quality and
microhardness of Cu-Zn-Al SMA alloy will be studied.
MATERIALS, EQUIPMENT AND
EXPERIMENTAL PROCEDURES
Materials: Mixing of three powder materials namely;
pure copper, pure Zinc and pure aluminum in approperate
percentages are normally used to prepare the Cu-Zn-Al
SMA. Its chemical composition by weight is shown in
Table 1.
Preparation Cu-Zn-Al shape memory alloy: The CuZn-Al SMA was prepared by melting the precalculated
amount of high purity copper powder at 1250ºC, then the
pre-calculated amounts of pure Al and pure Zn were
Table 1:Chemical composition by weight of Cu-Zn-Al shape memory
alloy
Material
Cu
Zn
Al
wt.%
70%
26%
4%
added to the melt in a graphite crucible. The melt was
steered for 2 min then poured to solidify in steel mold and
cooled in air. The Cu-Zn-Al shape memory alloy was
synthesized in the form of 14 mm diameter and 70 mm
length cylindrical rods using melting and casting
technique.
Recommended procedure to produce the Cu-Zn-Al
shape memory alloy (www.tiniaerospace.com): To
produce the shape memory alloy the following procedures
as reported in (www.tiniaerospace.com) was adopted in
the following sequence.
C
C
C
Heating the cast (Cu-Zn-Al) to 820ºC for 10 min
Quenching the cast material by oil at 120ºC for 5 min
Cooling the cast in water at room temperature
Equipment: A set of equipment was used in this
investigation; that are available in Tafila Technical
University:
C
C
C
C
Surface roughness tester (kosaka surfcorder SE3500).
CNC lathe machine (Boxford).
Digital microhardness tester (model HWDM-3).
The burnishing tool shown in Fig. 3.
The burnishing process: It can be seen from Fig. 3 the
mechanism of burnishing process, it can be used as a tool
on lathe machine that burnish the surfaces of cylindrical
parts. The tool inclined 45º.
Design and manufacturing of burnishing tool:
Burnishing tool design: The Pro-Engineer wildfire 2 was
used in this investigation to determine the stresses,
deformation and strain for burnishing tool. The tool made
from D3 steel that hardened and tempered.
Fig. 3: Roller burnishing process
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
Head design: A three burnishing forces were taken based
on previous study of Al-Qawabah namely 20, 92.5 and
212 N which cover the range of the tool. The free body
diagram of forces and boundary conditions of the head are
shown in Fig. 4.
After the running of pro-engineer program stress,
strain and deformation distribution at F = 20 N are
analyzed as shown in Fig. 5, 6 and 7 respectively. The
maximum stress according to von-mesis criterion is
5.8*10G1 MPa and the maximum strain is 1.8*10G6
mm/mm where the maximum displacement is 8*10!6 mm.
After the running of Pro-Engineer program stress,
strain, and displacement at F = 92.5 N are shown in
Fig. 8, 9 and 10. The maximum stress according to vonmesis criterion is 2.16 MPa and the maximum strain is
6*10G6 mm/mm where the maximum displacement is
7.3*10G5 mm.
Fig. 4: The head of burnishing tool
Fig. 5: Stress distribution according to von mesis criterion at 20 N
Fig. 6: Strain distribution (mm/mm)
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
Fig. 7: Displacement in mm
Fig. 8: Stress distribution according to von mesis criterion at 92.5 N
Fig. 9: Strain distribution (mm/mm) at 92.5 N
After the running of Pro-Engineer program stress,
strain and displacement distribution at F = 212 N are
shown in Fig. 11, 12 and 13. The maximum stress
according to von-mesis criterion is 3.85 MPa and the
maximum strain is 1.28*10G5 mm/mm where the
maximum displacement is 1.15*10G4 mm.
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
Fig. 10: Displacement in mm at 92.5 N
Fig. 11: Stress distribution according to von mesis criterion at 212 N
Fig. 12: Strain distribution (mm/mm) at 212 N
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
Fig. 13: Displacement in mm at 212 N
Fig. 14: Free boundary diagram of tool holder
Fig. 15: Stress distribution according to von mesis criterion at 20 N
Holder design: The free body diagram of forces and
boundary conditions of the tool holder are shown in
Fig. 14.
After the running of pro-engineer program stress,
strain, and deformation distribution at F = 20 N are
analyzed as shown in Fig. 15, 16 and 17, respectively.
The maximum stress according to von-mesis criterion is
9*10G1
MPa and the maximum strain is 4.83*10!4 mm/mm
where the maximum displacement is 3.57*10!1 mm.
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
Fig. 16: Strain distribution (mm/mm) at 20 N
Fig. 17: Displacement in mm at 20 N
Fig. 18: Stress distribution according to von mesis criterion at 92.5 N
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
Fig. 19: Strain distribution (mm/mm) at 92.5 N
Fig. 20: Displacement in mm at 92.5 N
Fig. 21: Stress distribution according to von mesis criterion at 212 N
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
Fig. 22: Strain distribution (mm/mm) at 212 N
Fig. 23: Displacement in mm at 212 N
(a)
(b)
Fig. 24: (a) Burnishing tool, (b) Lathe and burnishing tool
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
Table 2: Burnishing force calibration of the tool
Load (N)
Indicator reading X0.01 mm
20
2
40
3
92.5
8
159.5
14
212
19
259
23
279
25
After the running of pro-engineer program stress,
strain and deformation distribution at F = 92.5 N are
analyzed as shown in Fig. 18, 19 and 20, respectively.
The maximum stress according to von-mesis criterion is
345 MPa and the maximum strain is 1.73*10G3 mm/mm
where the maximum displacement is 1.43 mm.
After the running of pro-engineer program stress,
strain and deformation distribution at F = 212 N are
analyzed as shown in Fig. 21, 22 and 23, respectively.
The maximum stress according to von-mesis criterion is
580 MPa and the maximum strain is 2.68*10G3 mm/mm
where the maximum displacement is 2.13 mm.
A roller burnishing tool was manufactured; the
schematic photo of the burnishing tool and the burnishing
process are shown in Fig. 24.
The burnishing force calibration is shown in Table 2.
RESULTS AND DISCUSSION
In this section, the effect of the roller burnishing
process on the microhardness and surface quality of CuZn-Al shape memory alloy was presented and discussed.
Where the machined Specimens were burnished on a
CNC lathe machine and the Condition of Machine
(feed,burnishing force and rotational speed) shown In
Table 3 and the specimens with its parts showed in
Fig. 25.
Fig. 25: Designation of test specimens
Effect of burnishing force on the surface roughness for
Cu-Zn-Al SMA: Five specimens each specimen has 3
regional areas by which the burnishing conditions applied
as shown in Table 3. The investigations were applied at
different conditions then the optimum condition is
determined.
Effect of burnishing force on the surface roughness for
the specimen 1 of Cu-Zn-Al SMA at (N = 470 r.p.m, F
= 50 mm/min): It can be seen from Fig. 26 that the
surface roughness enhanced after burnishing process, the
best enhancing is 81.3% after applying 212 N burnishing
forces, this enhancement attributed to surface plastic
deformation which translate the tensile residual stresses to
compressive one.
Effect of burnishing force on the surface roughness for
specimen 2 of Cu-Zn-Al SMA at (N = 1120 r.p.m, F =
50 mm/min): It can be seen from Fig. 27 that there is a
slight improvement in the surface quality after increasing
the burnishing speed to N = 1120 rpm. Where the best
enhancement was 59.5% achieved at 212 N burnishing
force.
Table 3: Data of surface roughness and microhardness of SMA
NO. of work
pies
No. of level
Feed mm/min
Speed (r.p.m)
1
A
50
470
B
50
470
C
50
470
2
D
50
1120
E
50
1120
F
50
1120
3
G
50
1500
H
50
1500
I
50
1500
4
J
100
470
K
100
470
L
100
470
5
M
100
1120
N
100
1120
O
100
1120
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Burnishing
force (N)
20
92.5
212
20
92.5
212
20
92.5
212
20
92.5
212
20
92.5
212
Roughness
Ra (:m)
0.64
0.71
0.57
2.93
2.86
1.23
2.34
2.68
1.78
1.31
1.58
1.37
2.72
1.27
1.16
Surface hardness
(HV)
218
227
230
211
227
262
176
207
233
192
203
211
178
251
268
3.5
Ra_after burnishing
Ra_after burnishing
Ra_before burnishing
Ra_before burnishing
3.04
3.04
3.04
Surface roughness (Ra) ( m)
Surface roughness (Ra) (m)
Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
3.0
2.5
2.0
1.5
1.0
0.71
0.64
0.57
0.5
3.5
2.0
1.58
1.31
1.37
1.5
1.0
0.5
0
a (20N)
a (212N)
a (92.5N)
Burnishing force (N)
J (20N)
Fig. 26: Relationship between burnishing force and Ra
Ra_after burnishing
2.86
Ra_before burnishing
3.04
3.04
Surface roughness (Ra) (m)
Surface roughness (Ra) ( m)
3.04
2.5
2.0
1.5
1.23
1.0
0.5
0
D (20N)
E (92.5N)
Burnishing force (N)
F (212N)
3.5
3.04
3.0
3.04
2.5
2.0
1.27
1.5
1.16
1.0
0.5
0
M (20N)
N (92.5N)
Burnishing force (N)
O (212N)
Fig. 30: Relationship between burnishing force and surface
roughness Ra
Ra_after burnishing
Ra_before burnishing
2.79
2.79
2.68
2.79
Hv after burnishing
2.39
Hv before burnishing
2.5
Surface micro hardness (Hv)
Surface roughness (Ra) (m)
3.04
2.72
Fig. 27: Relationship between burnishing force and Ra
3.0
L (212N)
Ra_after burnishing
3.5
2.93
K (92.5N)
Burnishing force (N)
Fig. 29: Relationship between burnishing force and surface
roughness Ra
Ra_before burnishing
3.5
2.79
2.5
0
3.0
2.79
2.79
3.0
1.78
2.0
1.5
1.0
0.5
0
G (20N)
H (92.5N)
Burnishing force (N)
I (212N)
250
230
227
218
200
150
115
115
115
100
50
0
A (20N)
Fig. 28: Relationship between burnishing force and surface
roughness Ra
Effect of burnishing force on the surface roughness for
specimen (3) of Cu-Zn-Al SMA at (N = 1500 r.p.m, F
= 50 mm/min): It can be seen from Fig. 28 that there is a
slight improvement in the surface quality after increasing
the burnishing speed to N = 1500 rpm. Where the best
B (92.5N)
Burnishing force (N)
Fig. 31: Relationship between
microhardness of SMA
C (212N)
burnishing
force and
enhancement was 36.3% achieved at 212 N burnishing
force.
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Hv after burnishing
Hv after burnishing
Hv before burnishing
Hv before burnishing
300
Surface micro hardness (Hv)
Surface micro hardness (Hv)
Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
262
250
227
211
200
150
115
115
115
100
300
200
150
268
251
250
178
115
115
115
100
50
50
0
0
M (20N)
D (20N)
E (92.5N)
Burnishing force (N)
F (212N)
Fig. 32: Relationship between burnishing force and hardness of
SMA
Surface micro hardness (Hv)
Hv before burnishing
300
268
251
200
115
115
115
100
50
0
M (20N)
burnishing
force and
Effect of burnishing force on the surface roughness for
the five specimen of Cu-Zn-Al SMA at (N = 1120
r.p.m, F = 100 mm/min): It can be seen from Fig. 30 that
there is an improvement in the surface quality at
burnishing speed to N = 1120 rpm and after increasing the
feed rate to 100 mm/min, Where the best enhancement
was 61.8% achieved 212 N burnishing force.
178
150
Fig. 35: Relationship between
microhardenss of SMA
O (212N)
N = 470 rpm and 100 mm/min feed rate, Where the best
enhancement was 53% that achieved at 20 N burnishing
force.
Hv after burnishing
250
N (92.5N)
Burnishing force (N)
N (92.5N)
Burnishing force (N)
O (212N)
Fig. 33: Relationship between burnishing force and hardness of
SMA
Hv after burnishing
Hv before burnishing
Effect of burnishing force on the surface
microhardness for Cu-Zn-Al SMA:
Effect of burnishing force on the surface
microhardness for specimen No. 1 of Cu-Zn-Al SMA
at (N = 470 r.p.m, F = 50 mm/min): It can be seen from
Fig. 31 that the microhardness enhanced after burnishing
process, the best enhancing is 100% after applying 212 N
burnishing forces. There is a direct relation between the
burnishing force and the microhardness.
Surface micro hardness (Hv)
250
211
203
200
Effect of burnishing force on the surface
microhardness for specimen No. 2 of Cu-Zn-Al SMA
at (N = 1120 r.p.m, F = 50 mm/min): It can be seen from
Fig. 32 that the microhardness increased as the burnishing
force increase, the maximum is 127% that achieved at 212
N burnishing force.
192
150
115
115
115
100
50
Fig. 34: Relationship between burnishing force and hardness of
SMA
Effect of burnishing force on the surface
microhardness for specimen No. 3 of Cu-Zn-Al SMA
at (N = 1500 r.p.m, F = 50 mm/min): It can be seen
from Fig. 33 that the microhardness increased as the
burnishing force increase, the maximum is 133% that
achieved at 212 N burnishing forces.
Effect of burnishing force on the surface roughness for
specimen 4 of Cu-Zn-Al SMA at (N = 470 r.p.m, F =
100 mm/min): It can be seen from Fig. 29 that there is an
improvement in the surface quality at burnishing speed to
Effect of burnishing force on the surface micro
roughness for specimen No. 4 of Cu-Zn-Al SMA at (N
= 470 r.p.m, F = 100 mm/min): It can be seen from
Fig. 34 that the microhardness increased as the burnishing
0
J (20N)
K (92.5N)
Burnishing force (N)
L (212N)
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2682-2694, 2012
force and the feed rate increased, the maximum is 83.4%
that achieved at 212 N burnishing force.
Effect of burnishing force on the surface
microhardness for specimen No. 5 of Cu-Zn-Al SMA
at (N = 1120 r.p.m, F = 100 mm/min): It can be seen
from Fig. 35 that the microhardness increase as the
burnishing force increase, the maximum enhancement in
the hardness was 133.3% that attained at 212 N
burnishing force.
CONCLUSION
Form this study the following can be concluded:
C
C
The surface quality is enhanced after burnishing
process where the maximum enhancement is 81.3%
that attained after applying 212 N burnishing force at
470 rpm and 50 mm/min feed rate.
The surface microhardness is enhanced after
burnishing process where the maximum enhancement
is 133.3 that achieved after applying 212 N
burnishing force at 1120 rpm and 100 mm/min feed
rate.
ACKNOWLEDGMENT
This study has been supported by Tafila Technical
University which is acknowledged. Author also would
like to thank Eng. Tayseer Al-madani, Eng. Abd asalam
Al-smadee, Eng. Hanee Al-Rawshdeh and Eng. Ayman
Al-sharadedeh for their help in laboratory works.
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