a new ultrasonic aided laser joining method for bonding dissimilar materials has been developed . the method is capable of eliminating the laser - induced bubbles at the bonding faces and to improve the joint strength over that of the conventional laser - assisted metal and plastic joining method . some experiments on joining titanium to polyethylene terephthalate have been conducted to show the superiority of ual over lamp . the results showed that the joint strength , measured in terms of failure load , was significantly increased when ultrasonic vibration was employed during laser joining . for the lamp joined specimens , fracture normally occurred at the metal - plastic interface , whereas for the ual joined specimens , fracture normally occurred in the parent plastic part . the improvement in joint strength is mainly due to the elimination of pores in the resolidified plastic . in addition , ultrasound vibration promotes chemical bonding between the plastic and metal parts , and this is supported by the xps results .