One aspect provides a method of securing a feedthrough to a metal housing for an implantable medical device. The feedthrough is provided comprising an insulating section and at least one conductive section extending through the insulating section. At least a portion of the insulating section is metalized and the metalized feedthrough is placed within an opening in the metal housing of the implantable medical device. The feedthrough and metal housing are positioning within an ultrasonic welding system and the ultrasonic welding system is energized such that sonic energy welds the feedthrough directly to the metal housing. The temperature of the metal housing is not raised above the β-transus temperature of the metal housing during the ultrasonic welding.