Effect of atmosphere on the microstructure and properties of additively manufactured tungsten

The working atmosphere greatly affects the melting and solidification processes in powder-based additive manufacturing. In this work, pure tungsten components were fabricated by selective laser melting (SLM) under argon and nitrogen, respectively. The effects of the atmosphere and processing parameters on densification, microstructures, and phases were investigated. Tungsten processed under nitrogen exhibited a higher density, lower roughness, and superior mechanical performance than that processed under argon. The high dynamic viscosity of liquid tungsten in argon induced balling and pore formation during the laser melting process, leading to relatively low density and poor mechanical properties of the SLM-processed tungsten that was manufactured in argon. The results help to promote the practical application of SLM for complicated tungsten components in the nuclear and military industries.