Resistance spot welding of steel and aluminum with Cu/Zn bimetal interlayers: mechanical properties, microstructure and mechanisms
Year: 2025
Type: article
Abstract: To mitigate the formation of brittle intermetallic compounds during aluminum/steel welding, resistance spot welding (RSW) experiments were conducted using 6082-T6 aluminum alloy and DP590 steel with the incorporation of Cu/Zn bimetal interlayers. The microstructure and mechanical properties of the weld joints were analyzed using scanning electron microscopy, electron probe microanalysis , electron backscatter diffraction , and transmission electron microscopy . The results revealed that the Cu/Zn bimetal interlayers substantially increased the shear strength of the weld joints. As the welding current increased from 13 to 16 kA, the shear strength initially increased before declining, which was accompanied by a fracture-mode transition from interfacial fracture to button fracture. A maximum shear strength of 7.199 kN was achieved at a welding current of 15 kA, reflecting a 52 % improvement compared with joints without the interlayer. TEM analysis indicated the formation of novel phases, such as Fe 2 Al 5 Zn 0.4 and Al 2 Cu, with significant Cu and Zn enrichment on the Al side. Additionally, the intermetallic compound (IMC) layer thickness was reduced to 1.42 μm, representing an 81.44 % reduction relative to joints without the interlayer. These results indicated that the Cu/Zn bimetal interlayers effectively suppressed the growth of the IMC layer, improved the joint microstructure, and enhanced the mechanical performance of the welds.
Authors: Zikang Lu, Guoqiang You, Fanhong Kong, Jinyu Feng, Xuehua Lian, Bin Jiang
Institution: Chongqing University
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
Funder: Chongqing University
OpenAlex ID: W4410022245