Thermal and electrical aging of laser braze-welded aluminum–copper interconnects

in Translational Materials Research (2014), 1(1), 015001

Aluminum–copper (Al–Cu) interconnects are of great interest for a variety of electrical applications, such as lithium-ion batteries. In this paper, the effects of thermal and electrical aging on the ... [more ▼]

Aluminum–copper (Al–Cu) interconnects are of great interest for a variety of electrical applications, such as lithium-ion batteries. In this paper, the effects of thermal and electrical aging on the intermetallic compound growth of laser braze-welded Al–Cu interconnects are reported. Thermal aging was studied in a temperature range from 200 to 500 °C for durations between 1 and 120 h. Electrical aging was studied with 200 A direct current application with different polarities and durations between 1 and 24 h. The formation of intermetallic compounds was found to be dependent on the type of aging and, for electrical aging, on the polarity of the current. The growth of intermetallic compounds under the influence of the electric current was distinctly higher than for thermal annealing conditions. The formation of voids at the transition between intermetallic compounds indicates that electromigration may be the main driving force for the accelerated intermetallic growth. [less ▲]

Laser Assisted Joining of Hybrid Polyamide-aluminum Structures

in Physics Procedia (2014), 56(0), 845-853

Combined Laser Beam Braze-Welding Process for Fluxless Al-Cu Connections

in Dimitrov, Dimiter; Schutte, Corne (Eds.) PROCEDINGS International Conference on competitive Manufacturing, COMA 13 (2013, January)

A combined laser beam welding and brazing process for Al-Cu connections in overlap configuration is investigated. Aluminium and copper for electric and electronic application is used for experiments ... [more ▼]

A combined laser beam welding and brazing process for Al-Cu connections in overlap configuration is investigated. Aluminium and copper for electric and electronic application is used for experiments without surface treatment or activation, e.g. by flux. Although Al and Cu have been considered as “not weldable”, the possibility of a thermal joining process, i.e., the weld-brazing, was proved. The inevitable formation of intermetallic compounds at the interfacial region was reduced to less than 4 µm. Shear strength up to 51 MPa was achieved. A detailed fracture analysis has shown that the copper-rich intermetallic phase is the metallurgical weakest point due to the distinctive brittleness, even though the Al-rich Cu-phase is several times thicker. [less ▲]

Mechanical Properties of Laser Braze-Welded Al-Cu connections

in Mechanical Properties of Laser Braze-Welded Al-Cu connections (2012, November)

The paper describes an innovative, laser based joining method for dissimilar Al-Cu connections. The main objective is the improvement of the mechanical and electrical properties of the joints.

Laser Diffusion welding of Al-Cu connections

Scientific Conference (2012)