Joining of CFRTP and aluminum alloy thin plates using ultrasonic vibrations

Abstract

In order to realize light weight structure with multi-materials, this research applied ultrasonic joining method for dissimilar joining. As the joining members, aluminum alloy and CFRTP, CFRP using thermoplastic as base resin are selected because of their specific strength. By using ultrasonic joining system which generates maximum stress amplitude on joining plane, this stress fluctuation by ultrasonic application promote plastic flow in aluminum alloy. As a result, the plastic flow at interface remove resin of the CFRTP matrix, and the exposed carbon fibers are embedded in the Al alloy. Those mechanical interlocking at the interface enabled this dissimilar joining. Focusing on those effects caused by ultrasonic, we examined conditions that show high joining strength. By preparing specimens under various conditions, discuss relationship between joining conditions and joining strength by a series of cross tensile strength test. Moreover, the series of experiments with changing ultrasonic application time revealed that this joining method has the most suitable processing time, 0.8 s, and excess processing decrease its joining strength. Finally mechanism of this joining method has been discussed with the results of joining interface observation. And it was confirmed that carbon fibers embedded into Al alloy by plastic deformation form mechanical interlocking between carbon fiber and Al alloy.

Keywords

• ultrasonic vibrations
• joining
• plastic deformation
• cfrtp
• aluminum alloy
• multimaterialization