Dissimilar material welding between AA5052 and CFRP utilizing vaporizing foil actuator welding

Vaporizing Foil Actuator Welding(VFAW) process is one of explosion welding method which use a pressure of vaporized aluminum foil using high electric current. When actuator foil vaporized, the flyer moves toward the target at the velocity of several hundred meter per second. In VFAW process, contaminants on the colliding surfaces are removed during the impact in a form of jet. An impact angle between flyer and target sheet is very important process conditions in VFAW test because this oblique impact can eliminate the contaminants on colliding surface by utilizing high impact pressure between welding materials. The metallic bonding was formed between them which has high adhesive force after collision.

Al6061-T4(1.2t) and carbon fiber reinforced plastic plate(3t) was used for flyer and target sheet. In this case, the metallic bonding cannot be generated between welding surfaces because the carbon fiber doesn’t have a shared electron. A geometrical variable was adopted, which was a hole at the target sheet. CFRP was drilled with 10mm diameter to expected that the flyer sheet pass through the hole and weld with the wall of this hole. There was a possibility that the flyer sheet could be welded with the die set through the hole, so additional aluminum plate which was same with flyer sheet was placed between target sheet and die set. The standoff distance was set as 1.6 mm, and 10 kJ of input energy was applied among the various input energy conditions.

During the peeling procedure, the fracture occurred at the flyer sheet along the drilled hole so the welding between flyer sheet-additional Al plate was successful. It was expected that a bonding force from VFAW process was applied between drilled wall of CFRP and flyer sheet because additional aluminum was tightly attached after peeling of flyer sheet.