Preliminary Investigation on Embedding FBG Fibre within AA6061 Matrices by Ultrasonic Welding

Ultrasonic welding can be used to join plastic and metal through high- frequency (more than 20 kHz) acoustic vibrations. As the process is low tempera- ture and low pressure, it is easy to embed fragile sensors such as FBG fibre within metal matrices. In this research, the optimal parameters are obtained by experi- ments of tensile and nanoindentation hardness firstly. Then the microstructures are investigated in this paper to check the welding effect. The sensor effect of FBG fi- bre is also investigated. These experimental results clearly demonstrate that the strength and hardness of metal matrices will increase under ultrasonic welding. In addition, the temperature sensitivity of the nickel-coat FBG was improved after welding. From the experimental results, it is completely feasible to embed FBG fibre within AA6061 matrices by ultrasonic welding. Therefore, the 3-D smart metal structure can be made by the ultrasonic metal welding.