Selective laser melting of weak-textured commercially pure titanium with high strength and ductility: A study from laser power perspective

In this study, fully dense commercially pure titanium (CP Ti) parts were successfully fabricated by selective laser melting (SLM) using the same optimal laser energy density (Ep) over bar but with two different laser powers: high laser power E-H similar to 250 W and low laser power E-L similar to 50 W. It was found that at the same (Ep) over bar different laser powers led to different phase formation, microstructure, texture and mechanical properties of the selective laser melting fabricated (SLMed) CP Ti. A weak-textured CP Ti with isotropic mechanical properties was achieved using E-H while a strong -textured CP Ti with anisotropic mechanical properties was obtained using E-L. The underlying mechanism was attributed to the formation of alpha' phase in the CP Ti as a result of the higher cooling rates at E-H. The formation of a' phase also contributed to the observed high ultimate compressive strength similar to 1.1 GPa and high compressive strain >= 50% in the SLMed weak-textured CP Ti at E-H. This study provides important insights into the role of laser energy in the SLM fabrication of CP Ti with tailorable crystallographic texture and thus mechanical properties. (C) 2016 Elsevier Ltd. All rights reserved.