J. Cent. South Univ. (2022) 29: 38363846
DOI: https://doi.org/10.1007/s11771-022-5218-z
Role of oxides in the formation of hole defects in
friction stir welded joint of 2519-T87 aluminum alloy
YI Tie(易铁)1, LIU Sheng-dan(刘胜胆)1, 2, 3*, FANG Chen(方晨)1, JIANG Geng-duo(江耿铎)4
1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. National Key Laboratory of Science and Technology on High-strength Structural Materials
(Central South University), Changsha 410083, China;
3. Key Laboratory of Non-ferrous Metals Materials Science and Engineering of Ministry of Education
(Central South University), Changsha 410083, China;
4. School of Mechanical and Automotive Engineering, South China University of Technology,
Guangzhou 510640, China
© Central South University 2022
Abstract: The role of oxides in the formation of hole defects in friction stir welded joint of 2519-T87 aluminum alloy
has been investigated by using optical microscope, scanning electron microscope, electron backscatter diffraction and
electron probe microanalyzer to examine the distribution of oxides and the features of hole defects, and using ABAQUS
3D thermo-mechanical coupling finite element model based on arbitrary Lagrangian-Eulerian method to simulate the
material flow behavior. Oxides exist at the edge of tunnel hole and in the micropores in the joint. Based on distribution of
oxygen and material flow behavior, it is believed that the oxides on the surface of the alloy tend to flow down into the
bulk along the flow direction of plastic material during friction stir welding, aggregate in the weak region of material
flow at the intersection of the shoulder affected zone and the stir pin-tip affected zone, and consequently prevent the
material from contacting and diffusing. Due to the insufficient material flow and therefore the small plastic deformation,
the pressure is not high enough to compress the accumulated oxides, resulting in hole defects.
Key words: aluminum alloy; friction stir welding; arbitrary Lagrangian-Eulerian method; hole defects; oxides
Cite this article as: YI Tie, LIU Sheng-dan, FANG Chen, JIANG Geng-duo. Role of oxides in the formation of hole
defects in friction stir welded joint of 2519-T87 aluminum alloy [J]. Journal of Central South University, 2022, 29(12):
3836−3846. DOI: https://doi.org/10.1007/s11771-022-5218-z.
1 Introduction
Friction stir welding (FSW) is a solid-phase
welding technology and especially suitable for
aluminum alloys welding, because it can avoid
solidification defects caused by traditional fusion
welding [1 − 3]. However, there are still some
problems in friction stir welded aluminum alloys,
such as tunnel hole and micropores. These defects
are prone to stress concentration and become crack
initiation region, resulting in the deterioration of
mechanical properties in the joints [4−6]. Therefore,
it is essential to understand the formation of hole
defects in friction stir welded aluminum alloys to
improve the joint quality.
In some investigations, the formation of hole
defects was believed to be related to the insufficient
plastic flow of the material. For instance, HUANG
et al [7] investigated the formation of defects in
Received date: 2022-05-05; Accepted date: 2022-08-20
Corresponding author: LIU Sheng-dan, PhD, Professor; E-mail: lsd_csu@csu.edu.cn; ORCID: https://orcid.org/0000-0001-8547-0180
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J. Cent. South Univ. (2022) 29: 38363846
friction stir welded joints of Al-Mg-Si aluminum
alloy and thought that the main reason for tunnel
hole defects is that the plastic material could not
fully backfill the cavity on the advancing side. HAN
et al [8] found that insufficient heat input results in
poor fluidity in friction stir welded powder
metallurgy 2024 aluminum alloy, and hole defects
form if the plastic materials cannot reach the
position of the hole in time during welding.
SHOJAEEFARD et al [9] found that low rotation
and welding rates during FSW lead to low heat
input and increase the possibility of formation of
defects in friction stir welded joints of 7075-O and
5083-O aluminum alloys. In other investigations, it
is believed that the oxides on the surface of
aluminum alloy weldment mainly contribute to the
formation hole defects [10 − 14]. For instance, DAI
et al [13] examined the micropores in friction stir
welded joints of 6082-T6 aluminum alloy and found
a higher oxygen concentration on the edges of the
micropores, indicating the presence of oxide
particles near the micropores. ZHOU et al [14]
found the same phenomenon in friction stir welded
6082-T6 alloy joint. During welding, the oxides
may flow with the plastic materials, and then exert
complex effect on the formation of hole defects;
therefore, more investigations are needed to clarify
this issue.
Recently, some attempts have been made to
investigate material flow behavior during friction
stir welding or friction stir processing (FSP) using
numerical model to understand the formation of
hole defects better. For instance, CHAUHAN et al
[15] used a coupled Eulerian and Lagrangian
method to simulate the friction stir welding process
of 6061-T6 aluminum alloy and used volume of
fluid principle to predict the formation of defects
during the process. WEN et al [16] used an arbitrary
Lagrangian-Eulerian coupling method to simulate
the friction stir welding of 5052 aluminum alloy and
showed that increasing the tool rotating rate can
enhance the fluidity of materials and thus effectively
eliminate hole defects. AKBARI et al [17] used
Deform-3DTM software to simulate the material
flow during FSP and found that the materials on the
advancing side experience a higher amount of
effective strain than on the retreating side, and the
material deformation near the top surface is higher
than the near bottom area.
In this work, the role of oxides in the formation
of hole defects in friction stir welded joint of 2519T87 aluminum alloy has been investigated based on
experimental results of distribution of oxides and
the features of hole defects and the material flow
behavior simulated by finite element method. This
can help to better understand the formation
mechanism of hole defects and then eliminate them
in the FSW of aluminum alloys.
2 Experimental procedure
2519-T87 aluminum alloy sheets with a
thickness of 2.5 mm were used for FSW and the
chemical compositions are listed in Table 1. During
welding, the inclination angle of the rotation axis
and the press amount of the stir tool were 2.5° and
0.3 mm, respectively; the stir tool was inserted into
the weldment with a rotation rate of 1600 r/min and
a welding rate of 80 mm/min. Preheating to a low
temperature can soften the material and decrease the
axial downward pressure of the stir tool [18].
During welding, the weldment was preheated to
75 ℃ without causing grain coarsening of the base
metal. The weldments were all cooled to room
temperature in the air after welding.
Table 1 Chemical compositions of 2519-T87 aluminum
alloy
wt%
Cu
Mn
Mg
Ti
Zr
Fe
Si
Al
5.80
0.30
0.20
0.05
0.02
0.10
0.02
Bal.
Samples with sizes of 30 mm×15 mm×2.5 mm
were cut along the direction vertical to the welding
direction from the joint. The metallographic samples
were mechanically polished and etched in 30%
NaOH solution for about 30 s, and then immersed in
3% HNO3 solution to remove the corrosion products
on the surface. The samples were cleaned in water,
dried in still air, and examined by Leica DM2700M
optical
microscope.
Some
samples
were
mechanically polished first and then electrolytically
polished in an electrolyte of 10% HClO4+90%
CH3OH at 20 V for 6−8 s, and finally examined by
JSM-7900F scanning electron microscope with an
electron backscatter diffraction (EBSD) detector to
investigate grain structure. The distribution of
oxides in joint was examined by JXA-8230 electron
probe microanalyzer (EPMA). The morphology of
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hole defects in the joints were examined by Zeiss
MA 10 scanning electron microscope (SEM) and
Oxford EDS energy spectrum detector.
3 Mathematical modeling
3.1 Geometrical conditions and mesh generation
Because the adaptive remeshing of ALE
maintains high accuracy in large deformation during
FSW process, ABAQUS 3D thermo-mechanical
coupling finite element model (FEM) was used to
investigate the plastic flow behavior of welded
material [19−21].
The weldment was set as an undivided sheet in
the simulation process. To prevent meshes distortion
caused by excessive deformation in the process of
stir tool pressing down, a conical through hole
matching the stir pin was preset for the welding
part. To prevent the model meshes distortion caused
by the geometric corner of the stir pin-tip, the length
of the stir pin was set to be greater than the
thickness of the sheet. The stir tool was set as an
analytical rigid body and no meshing was carried
out. The geometry is shown in Figure 1. Physical
properties of H13 steel for stir tool can be found in
Ref. [22].
Figure 2 Displacement boundary condition
alloy are similar to 2219 aluminum alloy, so the
mechanical and physical parameters of 2219
aluminum alloy from Refs. [23 − 24] were used in
this work (see Figure 3). The Johnson-Cook semiempirical formula was used to describe the
relationship of flow stress, strain rate and
temperature [25] (see Eqs. (1) and (2)).
Figure 3 Mechanical and physical properties of 2219
aluminum alloy
σ = (A + Bεˉnp1 )(1 + Cln
Figure 1 Stir tool geometry in mm used in the simulation
and dimensions (Unit: mm; All corner radii are 0.2 mm)
In ALE model, non-uniform meshes were used,
i.e., fine meshes of 0.2 mm in the center zone of the
joint and coarser meshes in other zones; there are
6032 meshes and 7980 nodes (see Figure 2).
C3D8RT eight-node hexahedron reduced integral
displacement/temperature coupling solid element
were used.
3.2 Material properties
The chemical compositions of 2519 aluminum
εˉ̇ pl
)(1 - T *m )
ε̇ 0
ì 0 T < T 0
ï
ï T - Tm
*
 T0 £ T £ Tm
T =í
ï Tm - T0
ïî1 T 0 > T m
(1)
(2)
where σ is the flow stress; εˉpl is the effective plastic
strain; εˉ̇ pl is the effective plastic strain rate; ε̇ 0 is the
normalized strain rate; T is the temperature; T0 is
the initial temperature (75 ℃ ); Tm is the melting
temperature (542 ℃). The values of constants A, B,
C, n, m for 2519 aluminum alloy are from Ref. [26]
and presented in Table 2.
The elastic part of the material was described
by Hooke’s law. The mass scaling technique was
applied in the simulation [27] and the mass scaling
coefficient was 107. It is worthy to mention that the
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Table 2 Constants of Johnson-Cook model for 2519
aluminum alloy
A/MPa
B/MPa
C
n
m
ε̇ 0/s−1
452.7
282.6
1.42×10−2
0.42
0.74
1.0
mass scaling does not change the volume of heat
generated by plastic deformation work and friction
slip.
3.3 Boundary conditions
A thermo-mechanical finite element based on
the ALE formulation and adaptive remeshing were
applied in this work. The weldment was set as the
adaptive region. The upper and lower surfaces of the
weldment were set as the sliding surface. The
surface perpendicular to the joint was set as the
Eulerian surface to facilitate the inflow of materials.
In ALE model, velocity boundaries were used
in the Eulerian region to prevent material from
flowing out of the surface (see Figure 2). The
welding conditions used in the model, including the
inclination angle, press amount, rotation speed and
welding speed, were the parameters used for
welding in Section 2.
The penalty function friction model was used
for contact boundary and the coulomb law of
friction was applied. The friction coefficient
between the stir tool and the weldment was 0.4. The
contact type was finite slip friction. The rigid
surface of the stir tool was the principal surface and
the surface of the weldment was the minor surface.
The initial temperature of the weldment was
75 ℃ . The heat transfer coefficient between the
bottom and side of the weldment and the fixture was
200 W/(m2·℃) and the heat transfer coefficient
between the weldment and the air was 30 W/(m2·℃).
4 Results
4.1 Features of hole defects
According to the characteristics of the stir tool
action zone, the nugget zone (NZ) is divided into
shoulder affected zone (SAZ) and stir pin-tip
affected zone (SPTAZ) (see Figure 4). There are
micropores and tunnel hole on the advancing side
(AS) of the joint. The tunnel hole exhibits a wedged
shape from zone I in Figure 4. Micropores exhibit
small irregular shapes near the boundary between
NZ and the thermal mechanical affected zone
Figure 4 Local morphology of the advancing side of the
joint
(TMAZ). These defects are solid bonding defects
that located on the bonding line between SAZ and
SPTAZ.
The edge of the tunnel hole exhibits bright
contrast (see Figure 5(a)), and EDS results show
that oxygen element is densely distributed here (see
Figure 5(b)). Therefore, oxides are likely present in
this region. Oxygen element is also visible at the
micropores (see Figures 5(c) and (d)), and some
oxide particles in the micropores are detected. It is
related to the deterioration of material flow and the
accumulation of oxides and will be discussed in
Section 5.
It was found that the regions surrounding the
tunnel hole exhibit different grain structures (see
Figure 6(a)). Equiaxed grains are present in the SAZ
on the upper side of the hole, and their sizes are
(1.27±0.87) μm. Finer equiaxed grains exist in the
SPTAZ on the lower side of the hole, and their sizes
are (0.78±0.41) μm. It is because the shear rate and
heat generation on the top of the weld are higher
than that on the bottom of the weld [28]. Downward
migrating materials and upward migrating extruded
materials intersect here, but do not mix well, leading
to tunnel hole.
The compacted bonding line exhibits a good
metallurgical binding, but the grain structure is
different in this region (see Figure 6(b)). It is seen
that some ultra-fine grains are present in the center
of bonding line (see the arrows in Figure 6(b)), and
their sizes are about (0.47±0.11) μm. It is because
the flowing materials in compacted bonding line
experience severe plastic deformation, and the
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Figure 5 SEM images and oxygen mapping for hole defects of joint: (a) Tunnel hole from zone I in Figure 4; (b) Oxygen
distribution mapping of (a); (c) Micropores from zone III in Figure 4; (d) Oxygen distribution mapping of (c)
Figure 6 EBSD map of the regions surrounding the tunnel hole and compacted bonding line: (a) Tunnel hole in the
purple dotted frame of Figure 5(a); (b) Compacted bonding line from zone II in Figure 4
prolific dislocation wall and significant difference in
the stored energy between the neighboring grains
provide a favorable crystallographic condition for
the formation of ultra-fine grains [29].
The features of streamline and distribution of
oxygen in AS-TMAZ and NZ are shown by EPMA
images in Figure 7. The oxides flow path is roughly
consistent with the outer edge of the stir pin.
RAJAKUMAR et al [30] and ZHOU et al [31]
found that the internal oxides of joint mainly come
from the oxide film on the original weldment
surface and the oxidation products of aluminum
alloy form at high welding temperature. From
Figures 7(b) and (d), during welding, after being
broken and stirred, the oxide film and oxidation
products flow along the plastic flow direction of
material indicated by arrows, and continuous
streamline arrays of oxide particles form on the
cross-section of the joint.
4.2 Simulation results
The cross-section of the joint was examined.
The starting point is the time when the semicircle
behind the stir pin passes through the studied
surface, and the ending point is the time when the
semicircle behind the stir pin finally leaves the
studied surface. Figure 8 shows the flow velocity
distribution on the cross-section of the weldment
around the stir tool. The flow velocity of materials
on the joint surface is the highest and decreases with
the depth increasing. At the starting point (see
Figure 8(a)), the material flows slowly near the stir
J. Cent. South Univ. (2022) 29: 38363846
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Figure 7 EPMA map showing oxygen distribution: (a) Images of AS-TMAZ from zone IV in Figure 4; (b) Oxygen
distribution mapping of (a); (c) Images of NZ from zone V in Figure 4; (d) Oxygen distribution mapping of (c)
Figure 8 The material flow velocity profiles around the stir tool during FSW: (a) Starting point; (b) Mid-point;
(c) Ending point
pin-tip on the AS, as shown in the purple dotted
frame. This indicates that the shear speed at the stir
pin-tip is low, and the deformation resistance of the
edge material is large. In Figure 8(b), as the stir pin
leaves the studied surface, the material flow velocity
near the stir pin-tip on the AS is much lower. After
the stir pin completely leaves the studied surface
(see Figure 8(c)), the material near the stir pin-tip on
the AS stops flowing.
Based on the experimental results in Section
4.1, the hole defects tend to form in the purple
dotted frame in Figure 4 near the stir pin-tip on the
AS of the joint. Therefore, it is essential to focus on
this zone, and the equivalent plastic strain field is
shown in Figure 9. At the starting point (see
Figure 9(a)), the equivalent plastic strain at the edge
of the bonding line near the base material is
relatively small, which is caused by the greater
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Figure 9 The equivalent plastic strain field at the stir pin-tip on the advancing side during FSW: (a) Starting point;
(b) Mid-point; (c) Ending point
deformation resistance of the material due to lower
temperature. However, the equivalent plastic strain
tends to increase with the distance increasing away
from the base material (see the black dotted frame
of Figure 9(b)); it is likely due to the higher
temperature and reduced material deformation
resistance of the zone compared to the NZ edge
(Figure 9(a)). Then, as the stir pin moves away from
the studied surface, the equivalent plastic strain near
the stir pin-tip becomes smaller (see the purple
dotted frame of Figure 9(b) and (c)).
5 Discussion
It is an effective way to understand the
formation of defects by analyzing the material flow
behavior [32]. According to previous investigations
[33−35], the instantaneous cavity behind the stir pin
on the AS is filled with the down flow of plastic
material and upward flow of the extruded material,
and consequently, the joint forms after periodically
filling. During this process, if the materials cannot
fully contact and diffuse at the intersection on the
AS, e. g., prevented by oxides, it is easy for hole
defects to form.
Based on the experimental and simulation
results in Sections 4.1 and 4.2, respectively, the role
of oxides in the formation of hole defects during
FSW can be inferred. Firstly, from the distribution
of streamline arrays of oxides in the joint crosssection (Figures 7(b) and (d)), at the starting point,
it is reasonable that some dispersed oxides can flow
down with the plastic material, as described
schematically in Figure 10(a). Near the bonding line
of the base material, plastic flow deteriorates (see
the purple dotted frame of Figure 8(a)), and
therefore, the dispersed oxides accumulate to form a
discontinuous oxide film (Figure 5(c)). The
differences in the melting point and crystal structure
between aluminum and alumina make it impossible
for atomic diffusion to occur [36 − 37]. Therefore,
the oxide film hinders material contact and
diffusion,
as
described
schematically
in
Figure 10(b). Meanwhile, the pressure force
produced by small plastic deformation (Figure 9(a))
is not high enough to compress these materials,
leading to the micropores in zone III in Figure 4.
After the stir pin moves, the plastic deformation
becomes larger in the black dotted frame of
Figure 9(b), indicating strong intersection of the
materials; as a result, the bonding line is pressed
tightly, which can be seen in zone II in Figure 4 and
Figure 6(b).
As the stir pin moves away, the material flow
and the plastic deformation decrease in the purple
dotted frame of Figures 9(b) and (c). A number of
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Figure 10 Schematic of plastic flow at the stir pin-tip on AS during FSW: (a) Starting point; (c) Mid-point; (e) Ending
point; (b) Details of micropore in the purple dotted frame of (a); (d) Details of tunnel hole in the purple dotted frame of
(b)
oxide particles begin to accumulate and form a
sharp oxide layer edge in the purple dotted frame of
Figure 5(a), and therefore a higher pressure is
essential to form a strong metallurgical bonding.
However, this is unlikely to occur because as the
welding proceeds, the material flow becomes more
difficult, as shown in the purple dotted frame of
Figure 8(b). Then, the hole gradually expands
through the gap and the oxide layer separates the
material flow, as described schematically in
Figures 10(c) and (d). Finally, when the stir pin
completely leaves the studied surface, as described
schematically in Figure 10(e), the welded material
stops flowing (Figure 8(c)), and the cavity cannot be
fully filled, resulting in the tunnel hole from zone I
in Figure 4.
Therefore, to effectively eliminate the hole
defects during friction stir welding of aluminum
alloy, it is essential to reduce the content of oxide in
the weld and simultaneously increase the material
fluidity. It is known that mechanical cleaning or
chemical cleaning before FSW may be used to
eliminate the oxide film on the surface of aluminum
alloy weldments [38], to reduce the content of
oxide. And the material flow can be improved by
optimizing the process parameters and the geometry
of stir tool [39]. Recently, the auxiliary energy
method, such as laser and TIG assisted FSW, has
been developed to evaporate the oxide film on the
surface of aluminum alloy weldments and
simultaneously enhance the material flow [40 − 41].
This is a worthwhile topic for future investigations.
6 Conclusions
In this work, ABAQUS 3D thermo-mechanical
coupling FEM based on ALE method was used to
analyze the material flow of friction stir welded
joint, the synergistic role of oxides and material
flow in the formation of hole defects during FSW
was investigated.
1) In the friction stir welded joint of 2519
aluminum alloy, the hole defects are present on the
AS and located on the bonding line between SAZ
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and SPTAZ at the bottom of joint. The hole defects
are covered with dense oxides. The grains are larger
on the upper side than the lower side of the hole
defects.
2) During welding, oxides flow along the
direction of plastic flow of the material and
accumulate in the weak flow zone at the intersection
of SAZ and SPTAZ and contribute to the formation
of tunnel holes and micropores by preventing
materials contact and diffusion.
3) At the intersection of SAZ and SPTAZ, the
pressure generated by insufficient material flow
cannot compress the accumulated oxides, resulting
in hole defects; however, the pressure generated by
sufficient material flow can compress the
accumulated oxides, resulting in a compacted
bonding.
[5]
[6]
[7]
[8]
[9]
Contributors
The overarching research goals were
developed by LIU Sheng-dan and YI Tie. FANG
Chen and JIANG Geng-duo established the models
and analyzed the measured data. YI Tie conducted
the literature review and wrote the first draft of the
manuscript. LIU Sheng-dan checked and proofread
the draft of manuscript.
[10]
[11]
Conflict of interest
YI Tie, LIU Sheng-dan, FANG Chen and
JIANG Geng-duo declare that they have no conflict
of interest.
References
[1]
[2]
[3]
[4]
El-SAYED M M, SHASH A Y, ABD-RABOU M, et al.
Welding and processing of metallic materials by using
friction stir technique: A review [J]. Journal of Advanced
Joining Processes, 2021, 3(1): 1 − 20. DOI: 10.1016/j. jajp.
2021.100059.
KUMAR R D, MUTHUKUMARAN S, XAVIER V, et al.
Investigation of weld parameters on ductility, onion ring and
fracture behaviour of friction stir welded AA2219-T87 [J].
Journal of Central South University, 2019, 26(9): 2318 −
2327. DOI: 10.1007/s11771-019-4176-6.
JIAO Jun, LI Guo-peng, ZHAN Li-hua, et al. Effect of creep
ageing on mechanical properties and microstructure of 2219
aluminum alloy friction stir welding joint [J]. Journal of
Central South University (Science and Technology), 2021,
52(2): 368 − 375. DOI: 10.11817/j.issn.1672-7207.2021.02.
005. (in Chinese)
NARENDER M, MANOJ A, JAKIRAHEMED M D. Study
on defects repairing using friction stir technologies [J].
[12]
[13]
[14]
[15]
[16]
[17]
Materials Today: Proceedings, 2021, 44(1): 2373 − 2379.
DOI: 10.1016/j.matpr.2020.12.441.
HAN Wei-hao, LI Pei, LIU Nan, et al. Microstructure and
mechanical properties of friction stir welded powder
metallurgy AA2024 alloy [J]. Journal of Central South
University, 2022, 29(3): 871−882. DOI: 10.1007/s11771-0224962-4.
BALOS S, SIDJANIN L. Effect of tunneling defects on the
joint strength efficiency obtained with FSW [J]. Materials
and Technology, 2014,48(4): 491−496.
HUANG Yong-xian, XIE Yu-ming, MNEG Xiang-chen,
et al. Joint formation mechanism of high depth-to-width ratio
friction stir welding [J]. Journal of Materials Science
Technology, 2019, 35(7): 1261 − 1269. DOI: 10.1016/j. jmst.
2019.01.016.
HAN Wei-hao, LI Pei, LIU Nan, et al. Microstructure and
mechanical properties of friction stir welded powder
metallurgy AA2024 alloy [J]. Journal of Central South
University, 2022, 29: 871 − 882. DOI: 10.1007/s11771-0224962-4.
SHOJAEEFARD M H, BEHNAGH R A, AKBARI M, et al.
Modelling and Pareto optimization of mechanical properties
of friction stir welded AA7075/AA5083 butt joints using
neural network and particle swarm algorithm [J]. Materials &
Design, 2013, 44: 190 − 198. DOI: 10.1016/j.matdes. 2012.
07.025.
OKAMURA H, AOTA K, SAKAMOTO M, et al. Behaviour
of oxides during friction stir welding of aluminium alloy and
their effect on its mechanical properties [J]. Welding
International, 2002, 16(4): 266 − 275. DOI: 10.1080/0950
7110209549530.
SATO Y S, YAMASHITA F, SUGIURA Y, et al. FIB-assisted
TEM study of an oxide array in the root of a friction stir
welded aluminium alloy [J]. Scripta Materialia, 2004, 50(3):
365−369. DOI: 10.1016/j.scriptamat.2003.10.008.
CHEN Hua-bin, YAN Keng, LIN Tao, et al. The
investigation of typical welding defects for 5456 aluminum
alloy friction stir welds [J]. Materials Science and
Engineering A, 2006, 433(1 − 2): 64 − 69. DOI: 10.1016/j.
msea.2006.06.056.
DAI Q L, WANG X Y, HOU Z G, et al Microcavities
accompanying a zigzag line in friction stir welded A6082-T6
alloy joint [J]. Science and Technology of Welding and
Joining, 2015, 20(1): 68−74. DOI: 10.1179/1362171814Y.000
0000256.
ZHOU Ping, DAI Qi-lei, ZHANG Yuan-jie. Effect of S curve
micro-morphology on mechanical properties of friction stir
welded joint [J]. Hot Working Technology, 2019, 21(48):
49 − 57. DOI: 10.14158/j. cnki. 1001-3814.2019.21.011. (in
Chinese)
CHAUHAN P, JAIN R, PAL S K, et al. Modeling of defects
in friction stir welding using coupled Eulerian and
Lagrangian method [J]. Journal of Manufacturing Processes,
2018, 34: 158−166. DOI: 10.1016/j.jmapro.2018.05.022.
WEN X F, MIAO C H, CAO L J, et al. Numerical simulation
on material flow during friction stir welding of 5052 Al alloy
[J]. Hot Working Technology, 2022, 51(5): 105 − 109. DOI:
10.14158/j.cnki.1001-3814.20202439. (in Chinese)
AKBARI M, SHOJAEEFARD M H, ASADI P, et al. Wear
performance of A356 matrix composites reinforced with
J. Cent. South Univ. (2022) 29: 38363846
[18]
[19]
[20]
[21]
[22]
[23]
[24]
[25]
[26]
[27]
[28]
[29]
different types of reinforcing particles [J]. Journal of
Materials Engineering and Performance, 2017, 26(9): 4297−
4310. DOI: 10.1007/s11665-017-2901-6.
VERMA S, GUPTA M, MISRA J P. Effect of preheating and
water cooling on the performance of friction-stir-welded
aviation-grade aluminum alloy joints [J]. Journal of
Materials Engineering and Performance, 2019, 28(7): 4209−
4220. DOI: 10.1007/s11665-019-04183-z.
QI Wei. ABAQUS 6.14 super learning manual [M]. Beijing:
The People’s Posts and Telecommunications Press, 2016. (in
Chinese)
JAIN R, PAL S K, SINGH S B. Numerical modeling
methodologies for friction stir welding process [J].
Computational Methods and Production Engineering, 2017,
125−169. DOI: 10.1016/B978-0-85709-481-0.00005-7.
IORDACHE M, BADULESCU C, NITU E, et al. Numerical
simulation of friction stir welding (fsw) process based on
abaqus environment [J]. Solid State Phenomena, 2016, 254:
272−277. DOI: 10.4028/www.scientific.net/SSP.254.272.
JAIN R, PAL S K, SINGH S B. Finite element simulation of
pin shape influence on materialflow, forces in friction stir
welding [J]. International Journal of Advanced
Manufacturing Technology, 2018, 94: 1781 − 1797. DOI:
10.1007/s00170-0170215-3.
XU Wei-feng, LIU He-jin, ZHU Hong-qiang. Numerical
simulation of thermal field of friction stir welded 2219
aluminum alloy thick plate [J]. Transactions of the China
Welding Institution, 2010, 31(2): 63−66. DOI: 10.1155/2010/
293410. (in Chinese)
LU Xiao-hong, LUAN Yi-han, MENG Xiang-yue, et al.
Temperature distribution and mechanical properties of FSW
medium thickness aluminum alloy 2219 [J]. The
International
Journal
of Advanced
Manufacturing
Technology, 2022, 119(11): 7229 − 7241. DOI: 10.1007/
s00170-021-08505-1.
JOHNSON G R, COOK W H. A constitutive model and data
for metals subjected to large strains high strain rates and high
temperatures [J]. Engineering Fracture Mechanics, 1983, 21:
541−548. DOI: 10.1038/nrm3209.
LIU Wen-hui, HE Zhen-tao, CHEN Yu-qiang, et al. Dynamic
mechanical properties and constitutive equations of 2519A
aluminum alloy [J]. Transactions of Nonferrous Metals
Society of China, 2014, 24(7): 2179 − 2186. DOI: 10.1016/
S1003-6326(14)63330-6.
ANSARI M A, SAMANTA A, BEHNAGH R A, et al. An
efficient coupled Eulerian-Lagrangian finite element model
for friction stir processing [J]. The International Journal of
Advanced Manufacturing Technology, 2019, 101(1): 1 − 14.
DOI: 10.1007/s00170-018-3000-z.
BENAVIDES S, LI Y, MURR L E, et al. Low-temperature
friction-stir welding of 2024 aluminum [J]. Scripta
Materialia, 1998, 41(8): 809−815. DOI: 10.1016/S1359-6462
(99)00226-2.
HU Yan-ying, LIU Hui-jie, LI Dong-rui. Contribution of
ultrasonic to microstructure and mechanical properties of tilt
probe penetrating friction stir welded joint [J]. Journal of
Materials Science & Technology, 2021, 85: 205 − 217. DOI:
10.1016/j.jmst.2021.01.027.
3845
[30] RAJAKUMAR S, MURALIDHARAN C. Influence of
friction stir welding process and tool parameters on strength
properties of AA7075-T6 aluminium alloy joints [J].
Materials and Design, 2011, 32(2): 535−549. DOI: 10.1016/j.
matdes.2010.08.025.
[31] ZHOU Nan, SONG Dong-fu, QI Wen-jun, et al. Influence of
the kissing bond on the mechanical properties and fracture
behaviour of AA5083-H112 friction stir welds [J]. Materials
Science & Engineering A, 2018, 719: 12−20. DOI: 10.1016/j.
msea.2018.02.011.
[32] KUMAR R, SINGH R, AHUJA I P S. Repair of automotive
bumpers and bars with modified friction stir welding [J].
Journal of Central South University, 2020, 27(8): 2239 −
2248. DOI: 10.1007/s11771-020-4445-4.
[33] WU Chuan-song, ZHANG Wen-bin, SHI Lei, et al.
Visualization and simulation of plastic material flow in
friction stir welding of 2024 aluminium alloy plates [J].
Transactions of the Nonferrous Metals Society of China,
2012, 22(6): 1445 − 1451. DOI: 10.1016/S1003-6326(11)
61339-3.
[34] SALLOOMI K N. Fully coupled thermomechanical
simulation of friction stir welding of aluminum 6061-T6
alloy T-joint [J]. Journal of Manufacturing Processes, 2019,
45: 746−754. DOI: 10.1016/j.jmapro.2019.06.030.
[35] QIAN J W, LI J L, XIONG J T, et al. Periodic variation of
torque and its relations to interfacial sticking and slipping
during friction stir welding [J]. Science & Technology of
Welding & Joining, 2012, 17(4): 338 − 341. DOI: 10.1179/
1362171812Y.0000000001.
[36] SATO Y S, URATA M, KOKAWA H. Parameters controlling
microstructure and hardness during friction-stir welding of
precipitation-hardenable aluminum alloy 6063 [J].
Metallurgical and Materials Transactions A, 2002, 33(3):
625−635. DOI: 10.1007/s11661-0020124-3.
[37] MAHTO R P, KUMAR R, PAL S K. Characterizations of
weld defects, intermetallic compounds and mechanical
properties of friction stir lap welded dissimilar alloys [J].
Materials Characterization, 2020, 160: 110115. DOI:
10.1016/j.matchar.2019.110115.
[38] XIONG J P, ZHAO Y G, ZHOU Y, et al. Research progress
of removal for oxide films on aluminum alloy [J]. Plating
and Finishing, 2013, 35(11): 15 − 19. DOI: 10.3969/j.issn.
1001-3849.2013.11.004.
[39] MENG X C, HUANG Y X, CAO J, et al. Recent progress on
control strategies for inherent issues in friction stir welding
[J]. Progress in Materials Science, 2021, 115: 100706. DOI:
10.1016/j.pmatsci.2020.100706.
[40] XIA P Y, YI Y H, CAI A J, et al. Laser cleaning process of
2219 aluminum alloy anodic oxide film before welding [J].
Chinese Journal of Lasers, 2019, 46(1): 0102005. DOI:
10.3788/CJL201946.0102005. (in Chinese)
[41] YI Tie, LIU Sheng-dan, FANG Chen, et al. Eliminating hole
defects and improving microstructure and mechanical
properties of friction stir welded joint of 2519 aluminum
alloy via TIG arc [J]. Journal of Materials Processing
Technology, 2022, 310: 117773. DOI: 10.1016/j. jmatprotec.
2022.117773.
(Edited by YANG Hua)
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中文导读
氧化物在 2519-T87 铝合金搅拌摩擦焊接头孔洞缺陷形成中的作用
摘要使用光学显微镜、扫描电子显微镜、电子背散射衍射仪和电子探针显微分析仪研究了氧化物在
2519-T87 铝合金搅拌摩擦焊接接头孔洞缺陷形成中的作用并采用基于任意拉格朗日-欧拉方法的
ABAQUS 三维热力耦合有限元模型对材料流动进行分析。氧化物存在于接头隧道孔洞的边缘和微孔洞
中。根据氧元素的分布和材料的流动行为可知在搅拌摩擦焊接过程中合金表面的氧化物往往沿着
塑性材料的流动方向向下流动聚集在肩部影响区和搅拌针端部影响区交汇处的材料流动薄弱区域
并因此阻碍材料的接触和扩散。由于材料流动不足因此塑性变形较小导致产生的压力不足以压合
积累的氧化物从而导致孔洞缺陷产生。
关键词铝合金搅拌摩擦焊接任意拉格朗日-欧拉方法孔洞缺陷氧化物