Freeform fabrication of Ti–Al alloys by 3D micro-welding

3D micro-welding (3DMW) is a newly developed rapid prototyping method for metals. It combines a micro-tungsten inert gas (TIG) welding with a layered manufacturing method. A 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. A wide variety of metals and alloys can be used. The Ti–Al based intermetallic alloys have superior mechanical and chemical properties. However, the forming process is difficult and costly. We have tried to fabricate 3D objects of the Ti–Al alloy system by using several thin Ti and Al wires. Some simple objects with a unique microstructure or graded composition are demonstrated.