Characterization of Influences of Steel-Aluminum Dissimilar Joints with Intermediate Zinc Layer

Abstract

Brittle intermetallic phases are formed when steel and aluminum are joined. Therefore, it is difficult to use this combination of materials when applying the multimaterial design in the construction of load-adapted and weight-adapted structures. In order to largely avoid the formation of these brittle phases, joining processes based on diffusion processes, such as composite forging, depict a good solution approach. The materials are joined in a solid state. Furthermore, zinc additives are used to create the joint. Zinc forms a compound with both steel and aluminum without the formation of brittle phases. By combining the composite forging process with zinc additives, strength values of 26 N/mm2 can be reached. This is higher, in comparison to former investigations of resistance spot welded and clinched joints. The joint properties depend on the composition of the zinc interlayer. Small amounts of magnesium in the zinc interlayer affected the strength and ductility values. While the strength decreased by about 30% in contrast to the zinc layer without magnesium, the ductility increased by 60%. This effect was probably due to the metallurgical impact of the alloying elements on phase formation, as could be shown by energy dispersive X-ray spectroscopy (EDX) analyses of the joint zones. Thereby, it was shown that the brittle intermetallic phases are located only in small areas.

An Exploratory Study on Resistance Spot Welding of Titanium Alloy Ti-6Al-4V

“…To define the best quality of Ti-6Al-4V weld nugget strength, it is important to investigate the weld nugget’s physical and mechanical properties. The RSW parameters such as the welding current, time, and force are proved to be the most significant affected parameters to develop the weld nugget properties [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. Similar materials with different thicknesses were previously studied [ 23 , 24 ].…”

Soldering of steel sheets and zinc-coated aluminum by hybrid composite forging

“…A new approach is therefore the creation of a material joint by composite forging of aluminum and steel with a zinc interlayer. In the case of composite forging, form-fitting, forcefitting, and/or material-locking connections are produced by hot forming [17][18][19][20][21]. While joining, the materials are not transferred to the molten state during forming under heat.…”