Correlation between porosity and processing parameters in TiAl6V4 produced by selective laser melting

• The initial porosity of SLM Ti6Al4V was significantly reduced by applying a systematic processing strategy.
• Marginal applied energy densities - excessive or insufficient - lead to two different mechanisms of pore formation.
• The correlation between pore orientation, and morphology allowed revealing voids critical for mechanical performance.
• Process optimization should consider pore formation mechanisms besides overall porosity to achieve low-void microstructures.

This study presents the correlation between process parameters and porosity formation in a TiAl6V4 alloy produced by selective laser melting. The porosity is investigated by 2D and 3D methods aiming to identify the mechanisms of void formation, their morphology as well as volume fraction as a function of the energy density. An evident minimum volume fraction is observed between process parameters with significant overheating and insufficient fusion. It is shown that these two marginal regions define two mechanisms of void formation. Two dominant types of voids morphology are identified and examined regarding pore orientation versus their elongation, which together with the curvature distribution analysis allow revealing critical defects.

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