Martensitic transformations in Ti-6Al-4V (ELI) alloy manufactured by 3D Printing
Journal article, 2018

In the present investigation, Ti-6Al-4V ELI samples were manufactured by the powder-bed fusion (PBF) process using the laser sintering (LS) technology. Microstructure, chemical and phase constitution, and mechanical properties were studied by means of the transmission electron microscopy, atom probe tomography, X-ray diffraction, nanoindentation and mechanical testing. It was found that the structure of LS samples consisted of two different variants of metastable phases, namely the hexagonal α′ martensitic phase and small amounts of the orthorhombic α″ martensitic phase. The martensitic α′-phase was formed because of the high cooling rates of the LS method. The {101¯2} ⟨1¯011⟩ hexagonal martensite tensile twins were observed in the microstructure of the as-build alloy. Small areas with inner twinning martensitic plates, which are typical for the metastable orthorhombic martensitic phase in titanium alloys, were identified by the transmission electron microscopy. Atom probe tomography (APT) confirmed localization of β-stabilizing elements at interfaces, presumably at the twin or lamella boundaries. The structure and origin of the martensitic phases in 3D printed Ti-6Al-4V alloys are discussed with respect to in-situ heat treatment during manufacturing.

Titanium alloys

Mechanical properties

Metastable phases

Material or constituting phase(s)

Laser sintering

Author

N. Kazantseva

Russian Academy of Sciences

Ural Federal University

Pavel Krakhmalev

Karlstad University

Mattias Thuvander

Chalmers, Physics, Materials Microstructure

Igor Yadroitsev

Central University of Technology, Free State

N. Vinogradova

Russian Academy of Sciences

I. Ezhov

Russian Academy of Sciences

Materials Characterization

1044-5803 (ISSN)

Vol. 146 101-112

Subject Categories

Inorganic Chemistry

Materials Chemistry

Metallurgy and Metallic Materials

DOI

10.1016/j.matchar.2018.09.042

More information

Latest update

10/22/2018