In-situ measurement of relative motion during ultrasonic spot welding of aluminum alloy using Photonic Doppler Velocimetry

The bonding formation for ultrasonic welding of dissimilar metals has been shrouded in mystery because of the complex thermomechanical behavior at the bonding interface. We investigated the microstructure and phases at the bonding interface of ultrasonically welded aluminum to copper joints using transmission electron microscopy, and found a ~10 nm thick transition layer composed of amorphous phase and nanocrystallines, which was believed to form the bonding between these two metals in addition to mechanical interlocking observed at a larger scale. Interdiffusion of parent elements (i.e. Al and Cu) was noticed in the amorphous phase, which was mainly driven by plastic deformation in solid state introduced by ultrasonic vibration. High densities of dislocations and stacking faults were also observed in the parent metals close to the transition layer, confirming the effects of severe plastic deformation.

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“…Lu et al . 6 and Fujii et al . 7 presented that dynamic recrystallization might occur concurrently during ultrasonic welding.…”

Section: Introductionmentioning

confidence: 93%

Investigation of Interfacial Layer for Ultrasonic Spot Welded Aluminum to Copper Joints

Zhang

Wang

et al. 2017

Sci Rep

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“…The aforementioned interfacial phenomena are closely related to the relative motions of the bonding materials; moreover, the relative motion between the tool and the bonding material in contact with the tool surface is an important factor in ultrasonic bonding. A few researchers have observed the relative motion behavior by means of image correlation [17] and photonic Doppler velocimetry [18]. These studies have revealed that the interface at which relative motion occurs between materials changes to the interface between the tool tip and the materials as the bonding time increases, and the relative motion between the tool tip and the bonding material significantly influences bonding quality.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic Bonding of Multi-Layered Foil Using a Cylindrical Surface Tool

Arimoto

Sasaki

Doi

et al. 2019

Metals

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A cylindrical tool was applied for ultrasonic bonding of multi-layered copper foil and a copper sheet to prevent damage to the foil during bonding. The strength of the joints bonded with the cylindrical tool was comparable to that of the joints bonded with a conventional knurled tool. The effect of the cylindrical surface tool on bondability was investigated thorough relative motion behaviors between the tool surface and the bonding materials, as well as on bond microstructure evolution. The relative motion was visualized with in-situ observation using a high-speed camera and digital image correlation. At shorter bonding times, relative motions occurred at the bonding interfaces of the foil and the copper sheet. Thereafter, the relative motion between the tool and the bonding material became predominant owing to bond formation at the bonding interface, resulting in a macroscopic plastic flow in the bonded region. This relative motion damaged the foil in knurled tool bonding, and the cylindrical tool achieved bonding without any damage.

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“…In addition to parameters set in the welding machine control, workpiece-dependent and further machine-dependent influences have been described and their influence studied [2,6,7,[11][12][13][14][15][16][17]. Further machine-dependent influences include characteristics as the welding frequency, maximum welding power, amplitude and pressure range, horn and anvil geometry respectively their surface design [11,12]. Also, Fig.…”

Section: Joint Formation and Influences On The Processmentioning

confidence: 99%

Application of electrical power measurements for process monitoring in ultrasonic metal welding

et al. 2022

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For the production of e-mobility components such as cable harnesses, battery cells, power electronics, etc., ultrasonic metal welding is well-established process of choice. These electrical applications require high quality for every single connection; single points of failure and no possibility of repair after installation or commissioning are state of the art. At present, the prevailing binding mechanisms and their sensitivity to the numerous process influencing variables like base material hardness, surface, and cleanliness are still the subject of research. In order to ensure sufficient quality despite the lack of process understanding, random destructive testing is carried out during ongoing production. The welding systems’ internal monitoring methods are currently not sufficient to make a prediction of the joint quality achieved. To determine process phases and extract features regarding the joint formation, the observation of process vibrations at the horn, anvil, and the components using laser-doppler-vibrometry, laser triangulation sensors or other suitable external measurement technology is common. These methods require external accessibility to the measurement position, not given in the industrial production environment. In this study, measurements of the high-frequency power signal of the welding system are conducted, and several machine learning models for quality prediction are set up. To ensure the robustness, several disturbances, e.g., changing material hardness and cleanliness, are taken into account. Thus, it will be evaluated to what extent an industrially suitable quality monitoring can be implemented by means of electrical measuring technology and how much more accurate such an external measuring system is compared to the possibilities already available in the welding system.

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In-situ measurement of relative motion during ultrasonic spot welding of aluminum alloy using Photonic Doppler Velocimetry

Cited by 57 publications

References 28 publications

Investigation of Interfacial Layer for Ultrasonic Spot Welded Aluminum to Copper Joints

Investigation of Interfacial Layer for Ultrasonic Spot Welded Aluminum to Copper Joints

Ultrasonic Bonding of Multi-Layered Foil Using a Cylindrical Surface Tool

Application of electrical power measurements for process monitoring in ultrasonic metal welding

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