Intermetallic compounds at aluminum-to-copper electrical interfaces: effect of temperature and electric current

Braunović, M.; Alexandrov, Nikolai

doi:10.1109/95.296372

Cited by 143 publications

(63 citation statements)

References 4 publications

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“…Some DFT theoretical studies have dealt with microstructure alloy phase in surface including metastable precipitates formed during cooling of the alloy, as Guinier-Preston (GP) zones [16,17]. A multiscale approach [18] was applied to model Al 2 Cu-θ phase, and was validated by the comparison with the morphology and microstructural experimental data.…”

Section: Introductionmentioning

confidence: 99%

DFT Modelling of Cu Segregation in Al-Cu Alloys Covered by an Ultrathin Oxide Film and Possible Links with Passivity

Cornette

Costa

Marcus

2017

Metals

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Abstract:We modelled with Density Functional Theory (DFT) an Al-Cu alloy covered with a passive film, with several Cu concentrations (from the limit of the isolated atom to the monolayer) at the interface with the oxide, as well as Guinier-Preston 1 (GP1) zones. At low (respectively high) concentration, Cu segregates in the first (respectively second) metal layer underneath the passive film. The Cu monolayer is the most stable configuration (−0.37 eV/Cu atom). GP1 zones were modelled, with a three-copper atom cluster in the alloy. The GP1 zone is slightly favoured with respect to the Cu monolayer under the oxide film. A low (respectively high) Cu concentration induces an electronic workfunction increase (respectively decrease) by 0.3 eV (respectively −0.4 to −0.6 eV) as compared to pure Al. In contrast, without oxide, Cu segregation at the Al surface induces no workfunction change at low concentration and an increase of 0.3 eV of the workfunction at high concentration. Thus, the presence of oxide modifies the expected tendency of workfunction increase by adding a more noble metal. For the studied models, no spontaneous electron transfer occurs to the O 2 molecule.

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Section: Introductionmentioning

confidence: 99%

DFT Modelling of Cu Segregation in Al-Cu Alloys Covered by an Ultrathin Oxide Film and Possible Links with Passivity

Cornette

Costa

Marcus

2017

Metals

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“…The crystallized melt had a mix of Al(Cu) and Θ-phase in its composition, while diffusion layer consisted of γ 2 , δ, ζ 2 and η 2 phases. As reported by Braunovic and Alexandrov (1994) and Pfeifer et al (2012), the conductivity of Θ-phase is 12-16 MSm.m −1 (Fig. 7b), so the depth of penetration for the area where Θ-phase is presented is 300-320 µm.…”

Section: Resultsmentioning

confidence: 58%

“…The impact and properties of intermetallic compound interlayers have been widely explored in previous studies. The decrease in strength properties as a result of intermetallic formation was reported by Braunovic and Alexandrov (1994); Lee et al (2005); Liu et al (2011);Sheng et al (2011); Kim and Hong (2013); Uscinowicz (2013). Lee et al (2005) have reported the decline of electrical conductivity caused by the emergence of intermetallics in Al/Cu bimetals however in the study of Acarer (2012) no significant decrease in electrical conductivity was observed after the formation of small quantities of CuAl 2 phase between metals.…”

Section: Introductionmentioning

confidence: 45%

Investigación sobre fusión de contacto en materiales compuestos laminados Cu/Al

et al. 2016

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ABSTRACT:The study presents investigation of chemical composition, microhardness and electrical conductivity of Cu/Al laminated metal composite after heat treatment at temperatures higher than Cu-Al eutectic melting point. The Cu/Al bimetal was obtained via explosion welding. Chemical composition of the material after heat treatments was identified using EDS analysis. Eddy current testing was applied to investigate electrical conductivity of the composite's components. Strain-hardened zones were identified in the explosion welded composite. The experimental value of electrical conductivity of explosion welded composite was in good coherence with calculated by additivity rule results. Heat treatments resulted in the formation of multiple interlayers which had high microhardness value and had intermetallics in composition. The electrical conductivity of the identified interlayers was significantly lower than of Cu and Al. RESUMEN:Investigación sobre fusión de contacto en materiales compuestos laminados Cu/Al. Se presentan los resultados de composición química, microdureza y conductividad eléctrica obtenidos en materiales compuestos laminados Cu/Al, tratados térmicamente a temperaturas superiores a las del eutéctico Cu -Al. El bimetal Cu/Al fue obtenido por soldadura por explosión. La composición química del material tras los tratamientos térmicos se analizó por medio de análisis EDS (Espectroscopia de Energías Dispersiva de Rayos X). La conductividad eléctrica se midió mediante ensayos con corrientes Eddy. Las zonas endurecidas en el material soldado por explosión fueron identificadas. El valor experimental obtenido de la conductividad eléctrica está en concordancia con el calculado por la regla de las mezclas. Los tratamientos térmicos dan lugar a la formación de múltiples intercaras de alta dureza, compuestos de intermetálicos. La conductividad eléctrica de las intercaras identificadas es significativamente menor que las correspondientes al Cu y al Al.

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“…It is evident that the hardness is higher at the interface than on the base metals, which most likely results from the compositional change of the interfacial zone. A greater hardness of IMCs signifies very low mechanical integrity, thus leading to the brittleness of the Cu/Al couples [34]. The observed hardness value first increases and peaks at point 1 located at the IMCs/base material interface.…”

Section: Hardness Of the Cu/al Interfacementioning

confidence: 95%

Investigation on the interface of Cu/Al couples during isothermal heating

Han

Ben

Yao

et al. 2015

Int J Miner Metall Mater

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Abstract:The evolutionary process and intermetallic compounds of Cu/Al couples during isothermal heating at a constant bonding temperature of 550°C were investigated in this paper. The interfacial morphologies and microstructures were examined by optical microscopy, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, and X-ray diffraction. The results suggest that bonding is not achieved between Cu and Al at 550°C in 10 min due to undamaged oxide films. Upon increasing the bonding time from 15 to 25 min, however, metallurgical bonding is obtained in these samples, and the thickness of the reactive zone varies with holding time. In the interfacial region, the final microstructure consists of Cu 9 Al 4 , CuAl, CuAl 2 , and α-Al + CuAl 2 . Furthermore, these results provide new insights into the mechanism of the interfacial reaction between Cu and Al. Microhardness measurements show that the chemical composition exerts a significant influence on the mechanical properties of Cu/Al couples.

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Intermetallic compounds at aluminum-to-copper electrical interfaces: effect of temperature and electric current

Cited by 143 publications

References 4 publications

DFT Modelling of Cu Segregation in Al-Cu Alloys Covered by an Ultrathin Oxide Film and Possible Links with Passivity

DFT Modelling of Cu Segregation in Al-Cu Alloys Covered by an Ultrathin Oxide Film and Possible Links with Passivity

Investigación sobre fusión de contacto en materiales compuestos laminados Cu/Al

Investigation on the interface of Cu/Al couples during isothermal heating

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