Microstructure and mechanical properties of a novel β titanium metallic composite by selective laser melting

• Published in: Acta materialia Vol. 68; pp. 150 - 158
• Main Authors: Vrancken, B., Thijs, L., Kruth, J.-P., Van Humbeeck, J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15-04-2014; Elsevier
• Subjects: Additive manufacturing; Applied sciences; Exact sciences and technology; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Production techniques; Selective laser melting; Solidification; Surface treatment; Ti6Al4V; β Titanium alloys; β Titanium alloys; Additive manufacturing; Selective laser melting; Ti6Al4V; Solidification; Mechanical properties; Titanium base alloys; Composite material; Additive; Laser; Manufacturing; Microstructure; Ti6A14V; Laser fusion
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2014.01.018

Selective laser melting (SLM) is an additive manufacturing process in which functional, complex parts are produced by selectively melting consecutive layers of powder with a laser beam. This flexibility enables the exploration of a wide spectrum of possibilities in creating novel alloys or even metal–metal composites with unique microstructures. In this research, Ti6Al4V-ELI powder was mixed with 10wt.% Mo powder. In contrast to the fully α′ microstructure of Ti6Al4V after SLM, the novel microstructure consists of a β titanium matrix with randomly dispersed pure Mo particles, as observed by light optical microscopy, scanning electron microscopy and X-ray diffraction. Most importantly, the solidification mechanism changes from planar to cellular mode. Microstructures after heat treatment indicate that the β phase is metastable and locate the β transus at ∼900°C, and tensile properties are equal to or better than conventional β titanium alloys.