Laser shock micro clinching of Al/Cu

Abstract

The influences of ablative layer, soft punch, die depth, and laser energy on novel micro clinching of Al/Cu were investigated. Ablative layer thickness notably influenced metal flow including neck and interlock; the relationship between reasonable ablative layer thickness and certain laser energy range was summarized. Soft punch with 100 μm was more suitable than with other thickness for the process. In the joinable laser energy range, with increase of laser energy, interlock thickness gradually increased, whereas the neck and bottom thicknesses gradually decreased. The process window of Al/Cu combination was acquired, and a certain thickness difference which was at least 40 μm inevitably existed between the upper and lower metal foils. For every joinable combination, matching function of optimum die depth are derived based on Al and Cu foil thickness when the thickness of each metal foil was less than 200 μm. The single lap shearing test showed that the tensile strength and failure model of the joint both depended on neck and interlock thicknesses; only the joint that simultaneously formed a large interlock and large neck can attain a high joining strength.