Impact Welding of Aluminum Alloy 6061 to Dual Phase 780 Steel Using Vaporizing Foil Actuator

Dissimilar Materials Welding with a Standoff-Free Vaporizing Foil Actuator between TRIP 1180 Steel Sheets and AA5052 Alloy

“…To secure a sufficient flying distance, the TRIP1180 target sheet with a thickness of 1.2 mm has been stamped to have an indentation along the circular boundary as depicted in Figure 7, which is applied to the initial stacking for the standoff-free VFAW test. The preform die set is designed to impress a circular indentation [32] on the target sheet with a diameter and height of 30 mm and 1.6 mm since it has been validated in the conventional VFAW experiments [23][24][25]29,30] for guaranteeing the optimum welding area and flying distance. The design variables in the specification of the die set are represented in Figure 8.…”

“…This is why the welded specimen with applying the input energy of 10 kJ tends to exhibit comparable tensile strength to the AA5052 without showing delamination and early fracture at the interface. It is noteworthy that it is necessary to take into consideration optimum process parameters with correlating the amount of input energy, simultaneously, since the weldability between dissimilar materials from the VFAW test is not proportionally influenced by the amount of input energy only [24,26].…”

“…The vaporizing foil actuator welding (VFAW) is the one of the explosion welding, which does not involve the conventional full melting of the materials being joined. It applies substantially high pressure to the bottom of a flyer sheet as depicted in Figure 1a to make it collide with a target sheet, which tends to induce metallic bonding [22][23][24] at the interface for permanent welding. When a high current is instantly applied to the aluminum foil, it is vaporized from solid to gas, directly, which tends to generate tremendously high pressure as shown in Figure 1b.…”

Microstructure and Fracture Toughness of an Aluminum-Steel Impact Weld and Effect of Thermal Exposure

“…Although the range varies depending on the material pair, metallurgical bonds have been typically observed at velocities ranging between 300-1000 m/s and angles between 5-20 0 [2,[46][47][48]. Previous VFAW studies with aluminum (1XXX/2XXX/6XXX series) as the flyer material with thicknesses ranging between 0.5 mm and 2 mm, input energies between 6 kJ and 8 kJ, and standoffs of 1.6 mm and 2.5 mm have recorded impact velocities between 650 m/s to 900 m/s with successful metallurgical bonding [4,41,[49][50][51][52][53][54]. As the weld progresses the impact angle increases continuously, whereas the impact velocity decreases from a maximum at the inner edge of contact at the boundary of the unwelded zone to a minimum at the outer edge of contact, where there is no weld.…”