Processing of Ti-5553 with improved mechanical properties via an in-situ heat treatment combining selective laser melting and substrate plate heating

Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Holger Schwab, Matthias Bönisch, Lars Giebeler, Tobias Gustmann, Jürgen Eckert, Uta Kühn
In this study the Ti-based alloy Ti-5Al-5V-5Mo-3Cr (wt%) was processed using selective laser melting (SLM) while keeping the substrate plate at a constant temperature of 500°C. Cubic samples were successfully fabricated with a relative density of about 99%. Their microstructures were analysed and correlated with the mechanical properties and compared with the fabrication state of non-heated selective laser melted Ti-5553. Investigations by XRD, SEM and TEM revealed the formation of a microstructure composed of a β-phase matrix and finely dispersed α-phase plates when heating was conducted. The microstructure critically depends on the thermal history and was found to have a pronounced influence on the mechanical behaviour. The mechanical properties of the heated specimens showed an enhanced compressive strength of about 1600MPa while the deformability remained relatively high. These results demonstrate that selective laser melting is capable of creating bulk parts with improved mechanical by precipitation hardening realized by applying an additional substrate heating during the process.

Graphical abstract

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