Pure tungsten samples were prepared by the selective electron beam melting (SEBM) process. The effect of the SEBM process parameters on the density, microstructure and compression strength of pure tungsten was studied. In addition, the influence of substrate preheating temperature during SEBM was studied. A processing window for additive manufacturing of pure tungsten by SEBM was preliminarily determined. Pure tungsten samples with relative density of 99.5% and without obvious pores and microcracks were successfully fabricated. The as-built pure tungsten samples showed strong columnar grain structures. Compression strength along the columnar grains in the build direction was measured to be 1560 MPa. Fracture occurred predominantly along the columnar grain boundaries by decohesion, in addition to brittle transgranular fracture. Refinement and strengthening of the columnar grain boundaries are expected to improve the compression strength of the SEBM-fabricated pure tungsten.
