Ultrasonic metal welding uses high-frequency vibrations to weld materials together without melting them. The process involves applying vibrational energy from a transducer through a sonotrode to the materials being bonded. Key variables include clamping force, welding time, frequency, and amplitude. Ultrasonic welding can join dissimilar metals and is used to assemble electronics, make electrical connections, encapsulate parts, and in aircraft and nuclear applications.