A welding process involves a fixture for holding a workpiece and a welder, or welding electrode. The fixture imposes ultrasonic vibration on the workpiece. The welder vibrates during vibration, and is operable at a first voltage for elding and a second voltage for peening. The peening may occur while the weldmetal is crystallizing. The welding process may be a process of welding two parts together, or of filling a groove or other feature, or of applying or restoring a surface, or of applying a hard facing or ceramic to a parent metal or object. The weldmetal may be the same, or substantially the same, as the parent metal, or it may be different. The different material may be a ceramic material.