Metallographic Studies of Dissimilar Al-Cu Laser-Welded Joints Using Various Etchants

Abstract

The welding of Al and Cu is considered as difficult due to the formation of intermetallic compounds, which cause a brittle joint with increased electrical resistance. This paper investigates etching techniques that were used to contrast the intermetallic compounds for optical microscope analysis. A 0.5 mm AA-1050 sheet was welded to a 0.5 mm SF-Cu sheet in overlap configuration. The cross sections were etched by using 17 different reagents, including common Al-grade 2xxx etchants, Al-bronze etchants, and specific IMC etchants. A complete microstructural characterization, including the formation of intermetallic compounds, is presented. The experimental result showed that a clear distinction of metallurgic structures is possible, thus enabling a more detailed analysis of Al-Cu welds. It was found that etchants #09, #14, and #16 revealed best the four different intermetallic compounds θ-

Welding of Copper to Aluminium With Laser Beam Wavelength of 515 nm

“…For microstructural analysis, the joint cross-section is prepared by sectioning and moulding in the resin followed by grinding and polishing procedure to obtain a mirror polished surface. The moulding, grinding and polishing procedures are followed as outlined by [14].…”

Effect of Cu Content on the PBF-LB/M Processing of the Promising Al-Si-Cu-Mg Composition

“…In order to obtain an overview of the microstructural characteristics and perform a compositional map to observe the distribution of the alloying elements, a thorough investigation with the ZEISS EVO 15 SEM (Zeiss, Oberkochen, Germany) equipped with an EDS detector was carried out on the samples chemically etched with the Keller reagent. In order to obtain a great contrast between the Al matrix and the Al/Si/Al 2 Cu network, the samples were then chemically etched with the Tucker reagent, which mainly etched the Al matrix and slightly etched the Al-Si eutectic phase, highlighting the Al 2 Cu phase in the network well [34]. To obtain an accurate microstructural analysis at high magnifications, the samples were then observed with a Field Emission Scanning Electron Microscope (FESEM), FESEM Merlin Zeiss SEM (Zeiss, Oberkochen, Germany).…”