Process window for electron beam melting of Ti-6Al-4V

Abstract

Selective electron beam melting (EBM) is a powder-bed based additive manufacturing technique for the fabrication of dense metallic parts. As a free-form deposition process EBM offers a high degree of freedom in design and a highly efficient utilization of material. For a widespread industrial application the achievable build rate is a critical factor. In this paper the process window for Ti-6Al-4V is explored by varying beam current and scan speed in a wide range. The EBM specimens were characterized by their density, porosity size and distribution, chemical composition, microstructure, hardness and tensile strength. Key findings include: (1) the minimum line energy necessary to achieve full density, (2) parameter sets for increased build rates at full density, and (3) formation of α'-martensite at high scan rates.

Keywords:

• Selective electron beam melting
• Ti-6Al-4V
• Process window
• Microstructure
• Mechanical properties

Acknowledgements

The authors like to thank Kerstin Kümmel, Marion Eckhardt, Volkmar Schlegel, Ralf Hauser and Tina Richter for their experimental support.