Processing Refractory Metals by Powder Bed Based Additive Manufacturing

摘要

Powder bed based additive manufacturing is a highly promising production route for parts made of refractory metals. These materials naturally are characterized by a high melting point, a brittle to ductile transition at low temperatures and a high reactivity at elevated temperatures. Therefore, this material class is hard to process with conventional manufacturing methods e.g. casting and forging. Here, the variety of additive manufacturing methods offer different solutions depending on the requirements of the material. This contribution gives an overview of advantages and disadvantages of powder bed based additive manufacturing methods, evaluated for refractory metals. Among others the example of pure tungsten is presented and the challenges of processing this material, concerning e.g. cracks and oxygen pick up, are discussed. At last the process developments for improving the manufacturing of these alloys by laser and electron beam melting is introduced.