Selective laser melting of Ti6Al4V: Effect of laser re-melting

Microstructural inhomogeneity in additively manufactured materials affects the material properties. The present study aims in minimizing such microstructural inhomogeneity in Ti6Al4V alloy fabricated using selective laser melting (SLM) from the gas atomized powder. A detailed and systematic study of the effect of remelting on the microstructure and mechanical properties of Ti6Al4V was undertaken. Acicular alpha' martensite was present in all the samples (both in the as-built SLM and remelted) and the dimensions of the alpha' phase change with the number of melting steps. The hardness of the as-built SLM sample increased and the material got homogenized with an increasing number of meltings. The ultimate tensile strength was higher in the double- and triple-melted samples while the ductility was lower than the single-melted sample. The present results clearly prove that the number of remeltings play a significant role in determining the microstructure (homogenization of the microstructure) and the mechanical properties of the SLM-built materials.