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Ultrasonic Joining (U-Joining) of Metal-Composites Hybrid Joints E.E. Feistauer a,1,2, T. Ebel b,3, J.F. dos Santos a,1, S.T. Amancio-Filho a,1,2
Institute of Materials Research, a Materials Mechanics, 1 Solid State Joining Processes, 2 Advanced Polymer-Metal Hybrid Structures / b Metallic Biomaterials, 3Materials Design and Characterisation
Helmholtz-Zentrum Geesthacht • Max-Planck-Straße 1 • 21502 Geesthacht • Germany • Phone /Fax: +49 (0)4152 87-2066 / 2033 • www.hzg.de Contact: Eduardo E. Feistauer (technical requests), [email protected] / Prof. Dr. -Ing. Sergio Amancio (group leader), [email protected]
A new direct-assembly joining technology
Results Microstructural features
Summary
Heat development
25
Local mechanical properties
Global mechanical properties
U-Joining: Metal Injection Molding (MIMStruct) + Ultrasonic Welding Environmental friendly Energy efficient Faster in comparison to the state-of-the-art Localized heat development No solvent, adhesive or additional materials
Joining by mechanical interlocking due to the surface 3D reinforcement (metallic pins) and adhesion forces (polymer consolidation)
Figure 3: Schematically representation of the U-Joining process. (1) Positioning of joining parts, (2) Application of
ultrasonic vibration and axial force, (3) Softening of polymer by frictional heat at the interface and onset of pin insertion, (4)
Polymer consolidation and (5) End of the process and sonotrode retraction.
Figure 4: Process phases. P1 - Accomplishment of contact between MIMStruct
pins and composite, P2 - Coulomb friction and unsteady state viscous
dissipation, P3 - Steady state viscous dissipation, P4 - Complete pins’
penetration and creation of adhesive forces at the joint interface, and P5 -
Joint consolidation.
Ultrasonic Joining (U-Joining, pat. applic. EU 15163163.7 ) Phases of the process
GF-PEI
MIMStruct 4 Pins
TMAZ
GFPEI
Overlap area: 13 x 15mm MIMStruct thickness: 2.85 GFPEI thickness: 6.35 4 pins
Overlap area: 19 x 15mm MIMStruct thickness: 2.85 GFPEI thickness: 6.35 6 pins 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
0
400
800
1200
1600
2000
2400
2800
Pin-less reference 4 Pins MIMStruct 6 Pins MIMStruct
Lap
Shea
r For
ce [N
]
Displacement [mm]
Principles of the process
The U-Joining concept
A new approach to manufacture future damage-tolerant and crash-resistant lightweight alloy/composite hybrid structures has been introduced.
Figure 2: MIMStruct manufacture route. The manufacture is
based on the metal injection molding technology.
Figure 5: Cross-sectional view of a 4 pins joints.
Figure 11: Customized-lap shear tensile testing . 0 2 4 6 8 10 12 14 16 18150
225
300
375
450
525
600
675
750
344
629
Max
. Tem
pera
ture
[°C
]
Time [s]
Max. temp. R1 Max. temp. R2
Figure 9: Curves of maximum temperature obtained by infrared thermography.
Figure 7: Formation of micromechanical interlocking at the MIMStruct (3) and pins (4) surface due to the opened porous.
Figure 8: The molten PEI expelled during the process fills the pin cavities (1). No visual microstructural changes in the MIMStruct part (2). Residual porosity = 4.4 ± 0.7%.
Figure 12: Fracture surface of a 6-pins U-joint. The failure mechanism combines
shearing of the metallic pins and mixed cohesive-adhesive failure of the composite.
Figure 10: Microhardness maps for the 4 pins joints.
MIMStruct (EP 2 468 436 B1) production of 3d-structured parts
Figure 1: Potential application for the U-Joining are found in the automotive, aerospace and infrastructure sectors.
Preliminary assessment resulted in fast joining cycles (between 1.3 and 1.7 seconds)
The 3D reinforcement of MIMStruct parts was successfully inserted in the composite by means of ultrasonic energy
The thermal-mechanical processing does not changes the mechanical properties of the MIMstruct part
The hybrid joints showed improved lap shear strength and toughness in comparison to pin-less reference joints
Failure location
Potential application
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