Freeform fabrication of superalloy objects by 3D micro welding

3D Micro welding (3DMW) is a newly developed rapid prototyping method for metals. It is a combination of micro tungsten inert gas (micro-TIG) welding and a layered manufacturing method. The tip of a thin metal wire is melted by a micro-TIG welder to form a small metal bead. By building up metal beads layer by layer under computer control, a 3D metal object is eventually formed. The fabrication of simple 3D objects made of Inconel alloy 600 was studied. The interface between adjacent beads had good adhesion. No cracks or pores remained in the formed objects. The tensile strength, elongation, density, and Vickers hardness were measured and compared to those of the commercial superalloy. The obtained results suggest that actual micro components or tools of refractory metals with high strength and oxidization resistance can be formed without molds by 3DMW.