Effect of hot rolling on structure and mechanical properties of Ti-6Al-4V alloy parts produced by direct laser deposition

Direct laser deposition is an additive manufacturing method capable of producing large-scale titanium alloy parts. In this work, hot rolling process was applied to reduce the porosity and improve the tensile properties of Ti6Al4V parts produced by direct laser deposition additive manufacturing. The hot rolling performed at 950 degrees C in ambient atmosphere with 10% deformation per pass was found to significantly enhance the mechanical properties. The measured ultimate tensile strengths of the as-built and hot-rolled samples were similar to 850 and similar to 915 MPa, respectively. The elongation at break also increased, from 8.5 to similar to 15%. The total porosity volume was also decreased from 0.09 to 0.003%. Further increase of the accumulated strain up to 47% did not affect significantly the tensile properties.