Laser-induced multiple points ignition test in Al/Ni exothermic reactive film for crack propagation control

Abstract

Al/Ni multilayer film shows a self-propagating exothermic reaction when a minute external shock is applied. Using the reactive film as a heat source for soldering enables us to complete the bonding process instantaneously within a second because of its fast reaction propagation. However, cracks are introduced in the reacted NiAl layer after bonding, which becomes a big problem in the viewpoint of thermal and mechanical reliability. In this study, a laser-induced multiple points ignition technique is developed, and reaction propagation characteristics and crack introducing phenomenon are investigated toward crack propagation control.