Selective laser melting of pure molybdenum: Evolution of defect and crystallographic texture with process parameters

Pure Mo bulk samples were fabricated by selective laser melting (SLM) with various process parameters. Two microstructural characteristics, namely, defect and the crystallographic texture, were investigated in detail. The laser power, scan speed, and layer thickness were widely varied, and the effects of each parameter on the microstructure were evaluated individually. Lack of fusion pore and spherical keyhole pore were found. The porosity decreased with an increase in the volumetric energy density (VED). The crystallographic texture characteristics along the build direction were investigated using electron backscatter diffraction analysis. It was confirmed that, similar to other materials, pure Mo tends to forma crystallographic texture. A strong <110> fiber texture was observed at a high laser power (350 W) and low scan speed (400 mm/s). However, this <110> fiber texture changed completely to a <001> fiber texture when the scan speed was increased to 800 mm/s. Scan speed had a significant effect on the resulting texture characteristics directly. Other process parameters, laser power, layer thickness and hatch distance had an effect indirectly by changing the VED value on the texture. (C) 2020 The Authors. Published by Elsevier Ltd.